Chapter 11. The Six Opossums of Félix de Azara: Identification, Taxonomic History, Neotype Designations, and Nomenclatural Recommendations

BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofitpublishers, academic institutions, research libraries, and research funders in the common goal of maximizing access tocritical research.

Chapter 11. The Six Opossums of Félix de Azara: Identification,Taxonomic History, Neotype Designations, and NomenclaturalRecommendationsAuthor(s): Robert S Voss, Philip Myers, François Catzeflis, Ana PaulaCarmignotto, and Josefina BarreiroSource: Bulletin of the American Museum of Natural History, 331(1):406-433.2009.Published By: American Museum of Natural HistoryDOI: http://dx.doi.org/10.1206/582-11.1URL: http://www.bioone.org/doi/full/10.1206/582-11.1

BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in thebiological, ecological, and environmental sciences. BioOne provides a sustainable onlineplatform for over 170 journals and books published by nonprofit societies, associations,museums, institutions, and presses.

Your use of this PDF, the BioOne Web site, and all posted and associated contentindicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use.

Usage of BioOne content is strictly limited to personal, educational, and non-commercialuse. Commercial inquiries or rights and permissions requests should be directed to theindividual publisher as copyright holder.

http://dx.doi.org/10.1206/582-11.1

http://www.bioone.org/doi/full/10.1206/582-11.1

http://www.bioone.org

http://www.bioone.org/page/terms_of_use

http://www.bioone.org/page/terms_of_use

Chapter 11

The Six Opossums of Felix de Azara: Identification, Taxonomic

History, Neotype Designations, and Nomenclatural

Recommendations

ROBERT S. VOSS1, PHILIP MYERS2, FRANCOIS CATZEFLIS3,

ANA PAULA CARMIGNOTTO4, AND JOSEFINA BARREIRO5

ABSTRACT

Six species of Paraguayan didelphid marsupials (opossums) were described by the Spanishnaturalist Felix de Azara (1742–1821), whose nontechnical accounts were the basis for Latinbinomials in current use for several species. Unfortunately, some of Azara’s descriptions areproblematic and have long been a source of taxonomic confusion. In particular, the namescurrently used for two species of Thylamys are difficult to reconcile with Azara’s text. Herein wereview the nomenclatural status of Azara’s opossums and discuss relevant issues that affectbinomial usage. Among other results, we report the rediscovery of the holotype of Caluromyslanatus (Olfers, 1818), and we designate neotypes to preserve current usage of the namesThylamys macrurus (Olfers, 1818) and T. pusillus (Desmarest, 1804).

INTRODUCTION

El mundo era tan reciente, que muchas cosas

carecıan de nombre, y para mencionarlas habrıa

que senarlas con el dedo. (The world was so new

that many things lacked names, and in order to

talk about them it was necessary to point.)

—Gabriel Garcıa Marquez, Cien Anos de

Soledad

Although pointing is the oldest and leastfallible method for determining the applica-tion of names, biological nomenclature wasoriginally based on descriptions. Unfortunate-ly, many early naturalists were unaware of thecharacters that distinguish closely relatedtaxa, so their descriptions were often foundto apply to two or more superficially similarspecies. The late recognition that descriptions

alone are inadequate to determine stabletaxonomic usage was responsible for thedevelopment of the type concept and itscodification by international biological con-sensus in the mid-20th century (Mayr et al.,1953). Designating type specimens (the formalequivalent of pointing; Ghiselin, 1995) has thecrucial advantage that diagnostic charactersomitted in the original description can bedetermined by subsequent examination, andthis practice is now required for all newspecies. For older names based on diagnosti-cally inadequate descriptions, the Internation-al Code of Zoological Nomenclature (ICZN,1999: Article 75) permits the designation ofneotypes as necessary to resolve problems ofconflicting or ambiguous application.

The literature of Neotropical mammalogyis, unfortunately, replete with problematic

1 Division of Vertebrate Zoology (Mammalogy), American Museum of Natural History.2 Museum of Zoology, University of Michigan, Ann Arbor, MI 48109.3 Laboratoire de Paleontologie, Case-Courrier 064, Universite Montpellier 2, Place E. Bataillon, 34095 Montpellier Cedex-05,

France.4 Universidade Federal de Sao Carlos (Campus Sorocaba), Rodovia Joao Leme dos Santos (SP 264) km 110, Bairro Itinga, CEP

18052-780, Sorocaba–Sao Paulo, Brazil.5 Museo Nacional de Ciencias Naturales, C/ Jose Gutierrez Abascal 2, 28006 Madrid, Spain.

406

names based on old descriptions.6 Much ofthe larger South American fauna, for exam-ple, was first made known to the world atlarge through the publications of intrepidexplorer-naturalists such as Georg Markgraf(1610–1644; Whitehead, 1979) or amateurcollectors like Albert Seba (1665–1736; En-gel, 1937), whose nontechnical accounts werecited as bibliographic sources by Linnaeus(1758) and other early taxonomists. Amongthose explorers whose faunal descriptions arestill the primary authority for determiningthe application of mammalian technicalnames, however, none is more importantthan Felix de Azara (1742–1821).

Felix Francisco Jose Pedro de Azara yPerera, a Spanish military engineer with noformal biological education, was sent toBuenos Aires in 1781 to help map theboundary between Spanish and Portuguesepossessions in South America. Due to lack ofPortuguese interest, the border survey wasinterminably delayed, so Azara occupied histime for some 20 years by describing thegeography, indigenous cultures, mammals,and birds of the region now delimited byParaguay, Uruguay, and the Argentine prov-inces of Buenos Aires, Corrientes, EntreRıos, and Misiones. Among his considerableaccomplishments (Beddall, 1975; Mones andKlappenbach, 1997), Azara described some75 species of native mammals, of whichabout 80% were previously unknown toscience (Hershkovitz, 1987).

Azara’s mammalian descriptions first ap-peared in a French translation (Azara, 1801:hereafter, the ‘‘Essais’’), which was based ona preliminary Spanish draft completed in1796 and sent to his brother in Paris. Arevised draft, longer than the first anddiffering from it in certain details, wassubsequently published in Madrid (Azara,1802: the ‘‘Apuntamientos’’). Additional com-ments on mammalian identifications wereprovided in a later work summarizing hisSouth American travels and observations(Azara, 1809: the ‘‘Voyages’’). Throughoutthese publications, Azara used only vernac-ular (Amerindian and/or Spanish) names for

the species he reported, but his descriptionsserved as the bibliographic basis for Latinbinomials authored by Desmarest (1804),Oken (1816), Olfers (1818), and others.Although Azara dispatched specimens toMadrid on more than one occasion (Cabrera,1934b), few examples are known to havesurvived to the present day.

Azara’s descriptions are detailed enough topermit unambiguous identifications of manyspecies, but some have long been sources oftaxonomic confusion. Among the Latinnames based on Azara’s rats, for example,are several cases of problematic usage thathave only recently been resolved by neotypedesignation (Myers and Carleton, 1981;Musser et al., 1998). Scientific names basedon Azara’s opossums, the identification andtaxonomy of which are the topic of thisreport, include additional examples of am-biguous application that need to be fixed.

The cited bibliographic reference for mostof the scientific binomials associated withAzara’s opossums is the Essais of 1801, inwhich six species were described (table 1).However, the same six species were alsodescribed in the Apuntamientos of 1802, whichconstitutes another primary source of infor-mation about the specimens personally ex-amined by Azara. Neither the Essais nor theApuntamientos was illustrated, and the platesaccompanying the Voyages of 1809 do notdepict any marsupials. Therefore, with theexception of a single extant holotype (Cab-rera, 1916), all of the relevant informationregarding the application of technical namesfor Azara’s opossums is contained in his texts.

As explained below, textual informationprovided in the Essais and the Apuntamientosis sufficient to determine the application ofsome names based on Azara’s opossums, butnot others. Two cases of consistent usagerequire no remedial nomenclatural action,but four problematic cases merit attention.Below, we designate neotypes for two names,recommend that another be suppressed, andstate our opinion that a fourth should not beused to replace any currently accepted name.

Materials and Methods

Qualitative external and craniodental char-acters mentioned in this report are those

6 For relevant examples, see the accounts for Monodelphisbrevicaudata, Dasyprocta leporina, and Myoprocta acouchy inVoss et al. (2001).

2009 VOSS ET AL.: AZARA’S OPOSSUMS 407

defined and illustrated by Voss and Jansa(2003, 2009). Following Clemens (1966: 3),we identify the small upper molar cuspposterolabial to the paracone but anterola-bial to the metacone as stylar cusp C (styC).In those species of Thylamys that possesssuch a structure, styC contributes to the‘‘serrated’’ appearance of the stylar shelf(Solari, 2003; Carmignotto and Monfort,2006), which is only shallowly indented bythe ectoflexus; species of Thylamys that lackstyC have stylar shelves that are much moredeeply notched by the ectoflexus (Solari,2003; Carmignotto and Monfort, 2006).

External dimensions of examined specimens(in millimeters, mm) and weights (in grams, g)are those recorded by collectors. Except asnoted otherwise, collectors of specimens thatwe examined are known or assumed to havefollowed the standard American measurementprotocol (Hall, 1981): total length (TL) fromnose to fleshy tail tip, tail length (LT) fromdorsal flexure to fleshy tip, hind foot (HF)from heel to tip of longest claw, ear (Ear) from

notch to distal margin of pinna. We computedhead-and-body length (HBL) by subtractingLT from TL.

Craniodental measurements are those de-fined and illustrated by Voss et al. (2001: fig. 7)and Voss et al. (2004: fig. 2). Briefly, theseinclude condylobasal length (CBL: measuredfrom the occipital condyles to the anteriormostpoint of the premaxillae), nasal breadth (NB:measured across the triple-point sutures of thenasal, frontal, and maxillary bones on eachside), least interorbital breadth (LIB: mea-sured at the narrowest point across the frontalsbetween the orbits), zygomatic breadth (ZB:measured at the widest point across bothzygomatic arches), palatal length (PL: mea-sured from the anteriormost point of thepremaxillae to the postpalatine torus, includ-ing the postpalatine spine, if present), palatalbreadth (PB: measured across the labialmargins of the M4 crowns, at or near thestylar A position), maxillary toothrow length(MTR: measured from the anterior margin ofC1 to the posterior margin of M4), length of

TABLE 1Vernacular and Technical Names of Azara’s Opossums

Name in the Essaisa

Name in the

Apuntamientosb Latin name(s)c

Micoure premier, ou micoure proprement dit El Micure paraguayensis Oken, 1816d

leucotis Wagner, 1847

paraguayensis Allen, 1902

Micoure second, ou micoure laineux El Lanoso lanata Olfers, 1818

lanigera Desmarest, 1820

Micoure troisieme, ou micoure a queue grosse El Coligrueso crassicaudata Desmarest, 1804

crassicaudis Olfers, 1818

macroura Desmoulins, 1824

ferruginea Larranaga, 1923

Micoure quatrieme, ou micoure a queue longue El Colilargo marmota Oken, 1816d

macrura Olfers, 1818

grisea Desmarest, 1827

Micoure cinquieme, ou micoure a queue corte El Colicorto brevicaudis Olfers, 1818

wagneri Matschie, 1916

Micoure sixieme, ou micoure nain El Enano pusilla Desmarest, 1804

nana Oken, 1816d

nana Olfers, 1818

a Azara (1801).b Azara (1802).c Epithets based on Azara’s descriptions. All of these names were originally combined with Didelphis Linnaeus

(sometimes misspelled Didelphys), feminine in gender (ICZN, 2006), the genus commonly used for most American

marsupials throughout the early 19th century. The cited bibliographic reference for all but one of these names is the

Essais (Azara, 1801), the unique exception being Didelphis ferruginea Larranaga, 1923, which was based on the

description of the Coligrueso in the Apuntamientos (Azara, 1802).d Unavailable due to inconsistent use of binomial nomenclature in Oken’s work (ICZN, 1956).

408 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 331

molars (LM: measured from the anteriormostlabial margin of M1 to the posteriormost pointon M4), and length of M1–M3 (M1–M3:measured from the anteriormost labial marginof M1 to the posteriormost point on M3). Allcraniodental measurements were taken withdigital calipers while specimens were viewed at6–25 diameters magnification under a binoc-ular microscope. Craniodental measurements(which we recorded to the nearest 0.01 mm)are rounded to the nearest 0.1 mm in the tablesaccompanying this report.

Except as noted below, all analyzedcharacter data (qualitative and morphomet-ric) were obtained from adult specimens asdetermined by dental criteria. FollowingVoss et al. (2001), a specimen was judged tobe juvenile if dP3 is still in place; subadult ifdP3 has been shed but P3 and/or M4 are stillincompletely erupted; and adult if the per-manent dentition is complete.

Institutional abbreviations associated withexamined specimens are: AMNH (AmericanMuseum of Natural History, New York),BMNH (Natural History Museum, London),FMNH (Field Museum of Natural History,Chicago), MNCN (Museo Nacional deHistoria Natural, Madrid), MNHNP (MuseoNacional de Historia Natural del Paraguay,Asuncion), MSB (Museum of SouthwesternBiology, Albuquerque), MVZ (Museum ofVertebrate Zoology, Berkeley), MZUSP(Museu de Zoologia, Universidade de SaoPaulo), OMNH (Oklahoma Museum ofNatural History, Norman), TTU (Museumof Texas Tech University, Lubbock), UMMZ(University of Michigan Museum of Zoolo-gy, Ann Arbor), USNM (National Museumof Natural History, Washington). The prefixTK identifies field numbers associated withspecimens collected by Robert Owen’s Para-guayan mammal inventory project (these willeventually be deposited at MNHNP or TTU;R. Owen, personal commun.), and the prefixTWN identifies field numbers associated withspecimens collected by Thomas W. Nelson(to be deposited in the Biological Collectionsof the University of Connecticut).

AZARA’S SIX OPOSSUMS

Azara referred to opossums generically as‘‘micoures’’ (in the Essais) or as ‘‘fecundos’’

(in the Apuntamientos). Because the sequencein which the species were described is thesame in both the French and Spanish texts(table 1), it is convenient to follow hisenumeration in the following accounts. En-glish translations of relevant passages in theApuntamientos are provided in appendix 1.

The First Opossum

Azara’s first opossum clearly correspondsto the species currently known as Didelphisalbiventris Lund, 1840, an identification sup-ported by many features described in both theEssais and the Apuntamientos. These includeits large size (e.g., maximum total length.800 mm); bold facial markings (black maskand midfrontal streak); white-tipped ears;white underfur; very long guard hairs; a largepouch that opens anteriorly and contains 11to 13 teats; and a prehensile, basally furredtail, the naked epithelium of which is blackishproximally and whitish distally.

The oldest Latin binomial that is unam-biguously based on Azara’s first opossum isDidelphis paraguayensis Oken (1816), butOken’s work is not available for nomencla-tural purposes (Hershkovitz, 1949; ICZN,1956). Didelphis paraguayensis is, however,available from Allen (1902), who used it as avalid name citing Azara’s account as itsbibliographic basis. Didelphis leucotis Wag-ner (1847) is also based on Azara’s descrip-tion of his first opossum, so paraguayensisAllen and leucotis Wagner are objectivesynonyms, and both are subjective juniorsynonyms of albiventris Lund.

Thomas (1888) and Cabrera (1958)thought that Didelphis azarae Temminck(1824) was based on Azara’s first opossum,and they used it as the oldest available namefor the white-eared Paraguayan species.Although Temminck cited Azara’s firstopossum as a synonym of D. azarae, his des-cription was actually based on several spec-imens of black-eared opossums that heexamined in various European museums(Wagner, 1847; Hershkovitz, 1969; Cerqueiraand Tribe, 2008). Whether azarae is a juniorsynonym of the black-eared Amazonianspecies D. marsupialis Linnaeus, 1758, or asenior synonym of the southeastern Brazilianspecies currently known as D. aurita Wied,


1826, remains to be determined by examina-tion of Temminck’s original material (said byhim to be in Paris, Leiden, Vienna, andFrankfurt). In the event that Temminck’ssyntypes should all prove to be from south-eastern Brazil, we recommend that azarae besuppressed in order to maintain current usage(Gardner, 1993, 2005; Cerqueira and Tribe,2008).

The Second Opossum

The next marsupial described by Azara islikewise unambiguously recognizable, corre-sponding to the species currently known asCaluromys lanatus (Olfers, 1818). This iden-tification is supported by many details ofAzara’s description (including external mea-surements, presence of a dark midrostralstripe, violet ears, woolly pelage, a tail that isfurred more extensively dorsally than ven-trally, etc.) and also by a fluid-preservedspecimen that he sent to Madrid. BecauseOlfers explicitly based lanatus on Azara’s(1801) description of the ‘‘Micoure second,’’and because Azara stated that he had seenbut a single example, the Madrid specimen isthe holotype by monotypy. Prior to therediscovery of Olfers’ rare and obscure work(Hershkovitz, 1959), this species was widelyknown as C. lanigera (Desmarest, 1820), anobjective junior synonym.

The holotype of Caluromys lanatus wasnot found in the Museo Nacional de HistoriaNatural by Delibes and Garcıa-Valdecasas(1987), who stated that no types of nonchir-opteran mammals were present in the collec-tion. However, a recent search by one of us(J.B.) happily resulted in the rediscovery ofAzara’s specimen (figs. 1, 2). Originallypreserved in alcohol with registration number528 (Cabrera, 1916), the type was subse-quently prepared as a skin and skull andrecataloged as MNCN-M2630. Althoughboth skin and skull are in good condition,the pelage is discolored from long immersionin alcohol. The specimen is a juvenile (withunreplaced dP3/dp3), so Azara’s publishedmeasurements (in appendix 1) do notrepresent mature anatomical dimensions.The type locality—stated in the Essais butnot in the Apuntamientos—is Caazapa

(26u099S, 56u249W; Paynter, 1989) in Depar-tamento Caazapa, Paraguay.

The Third Opossum

Azara’s (1801) description of the ‘‘Micourea queue grosse’’ was the basis for Lutreolinacrassicaudata (Desmarest, 1804), the identifi-cation of which does not appear to have everbeen questioned in the literature.7 Diagnostictraits mentioned by Azara include externalmeasurements; a thick, nonprehensile (orweakly prehensile), basally furred, white-tipped tail; the absence of any circumocularmask or other facial markings; small ears; aweakly defined pouch; and a conspicuouslycarnivorous captive diet. The epithets crassi-caudis Olfers (1818), macroura Desmoulins(1824), and ferruginea Larranaga (1923) areobjective junior synonyms.

In the Essais, Azara said that he saw a liveanimal of this species at the ‘‘village de Saint-Stanislaw’’ (5 San Estanislao at 24u399S,56u269W in the Paraguayan department ofSan Pedro; DMA, 1992), and that he hadexamined a female specimen from Asuncion.Neither locality is mentioned in the Apunta-mientos, however, where the species is simplysaid to occur in Paraguay and Buenos Aires.Several nominal subspecies of Lutreolinacrassicaudata have been recognized by au-thors within the Spanish territory traversedby Azara, including (in addition to thenominotypical form), L. c. bonaria Thomas,1923 (with type locality near Buenos Aires);L. c. lutrilla Thomas, 1923 (with type localityin Rio Grande do Sul, but ranging intoUruguay); and L. c. paranalis Thomas, 1923(with type locality in the Argentine provinceof Santa Fe). All of these are currentlytreated (e.g., by Gardner, 2005; Stein andPatton, 2008) as synonyms of L. c. crassi-caudata, but in the event that any aresubsequently recognized as valid taxa, itmight be desirable to fix the application ofcrassicaudata by neotype selection. Given thewidespread assumption that the nominotypi-cal form is the one that occurs in Paraguay(Thomas, 1923; Cabrera, 1958; Ximenez,

7 Cabrera (1934a) identified Azara’s ‘‘coligrueso’’ as Marmosagrisea (5 Thylamys macrurus, see below), but this was an obviouslapsus that he subsequently corrected (Cabrera, 1958).


1967), it would be appropriate to designate aneotype from that country. However, notaxonomic purpose would be served by doingso at this time.

The Fourth Opossum

Azara’s long-tailed opossum (the ‘‘Mi-coure a queue longue’’ of the Essais and the

Fig. 1. Dorsal and ventral views of the skin of the holotype of Caluromys lanatus (Olfers, 1818) in theMuseo Nacional de Ciencias Naturales in Madrid (MNCN-M2630). Cabrera (1916) summarized thedocumentary evidence that this is Azara’s original and unique specimen of his second opossum.


Fig. 2. Dorsal and ventral views of the skull and mandibles of the holotype of Caluromys lanatus(Olfers, 1818) in the Museo Nacional de Ciencias Naturales in Madrid (MNCN-M2630). The presence ofupper and lower milk premolars (dP3/dp3) indicate that this is a juvenile individual.


‘‘Colilargo’’ of the Apuntamientos) was thebasis for three Latin binomials: Didelphysmarmota Oken, 1816; Didelphys macruraOlfers, 1818; and Didelphis grisea Desmarest,1827. As noted above, Oken’s names aretechnically unavailable, so Olfers’ is thesenior of these objective synonyms. Theobscurity of Olfer’s work (Hershkovitz,1959) explains why only Desmarest’s namewas widely used in the 19th-century litera-ture.

In both the Essais and the Apuntamientos,Azara said that his description was based ona single male specimen, possibly immature,that was sent to him by his friend Don JosefCasal. In the Apuntamientos this specimen issaid to have come from Don Josef’s countryhouse, but the Essais gives the place of originas ‘‘Tapoua.’’ According to Tate (1933: 218),this locality is ‘‘Tapua . . . some few milesnortheast of Asuncion,’’ which would put itin the Paraguayan department of Central.Gardner (2005: 17), however, stated that‘‘Tapua’’ (with an acute accent on theterminal vowel) is in Departamento Presi-dente Hayes. The geographic discrepancy issignificant because the departments of Cen-tral and Presidente Hayes lie on oppositebanks of the Rıo Paraguay, which divides thecountry into two ecologically and zoogeo-graphically distinct parts (Myers, 1982): theEastern Region and the Chaco (fig. 3).Fortunately, Azara’s posthumously pub-lished treatise on the geography of Paraguay(Azara, 1904; edited by R.R. Schuller) makesit clear that Don Josef’s house (in the vice-parroquia of Tapua, not Tapua) was in theEastern Region not far from the left bank ofthe Rıo Paraguay.

As described by Azara, his fourth opossummeasured 237 mm in total length and the tailwas 135 mm; by subtraction, the combinedlength of head and body was 102 mm. Aconspicuous black mask surrounded eacheye, and around each black marking was aborder of paler fur; between the left and rightmasks with their pale borders was a darkmedian line that terminated anteriorly at thelevel of the inner canthus of the eye. Thecolor of the fur between the ears, over thewhole back, and on the tail was said to be likethat of the house mouse, but the flanks werepaler, as were the sides of the forelegs. The

lower jaw, the throat, and the anterior partsof the forelegs were almost white, and the restof the ventrum was dirty whitish. All of thefur was short and soft.

Although Azara’s measurements and de-scription of his fourth opossum correspondplausibly with the external characters of thespecies currently known as Thylamys ma-crurus (see Carmignotto and Monfort, 2006),no unambiguously diagnostic traits are men-tioned in either the Essais or the Apuntamien-tos. In fact, Azara’s description has beenstretched to fit several other small didelphids.Thomas (1888), for example, identifiedAzara’s Micoure a queue longue with thespecies currently known as Marmosops in-canus, for which he used the name Didelphys(Micoureus) grisea Desmarest. Later (Thom-as, 1894), he changed his mind and used thename Micoureus griseus for a specimen ofThylamys collected in Corrientes, Argentina.After discovering the priority of Oken’s name,Thomas (1896) used Marmosa marmota forwhat he believed to be the same species inParaguay and Corrientes, but he subsequently(Thomas, 1912) designated one of his Cor-rientes specimens as the type of Marmosacitella, a new species. Currently, citella isregarded (e.g., by Gardner, 2005; Creightonand Gardner, 2008) as a junior synonym ofThylamys pusillus (Desmarest, 1804), a namebased on Azara’s sixth opossum (see below).

Tate (1933) used the name Marmosamarmota marmota (Oken) for the largeThylamys that occurs in eastern Paraguay,but he also recognized a smaller form in theChaco that he identified as M. marmotaverax Thomas (1921). Cabrera (1958) usedMarmosa (Thylamys) grisea (Desmarest) forthe taxon that Tate (1933) called M. marmotamarmota and referred verax to the synonymyof M. (T.) pusilla. As if the situation were notsufficiently confusing by this time, Hershko-vitz (1959) argued—not without reason (seebelow)—that Azara’s fourth and sixth opos-sums were conspecific and used the name M.pusilla (Desmarest, 1804) for both. However,Kirsch and Calaby (1977) recognized M. (T.)grisea and M. (T.) pusilla as valid speciesbased on Azara’s fourth and sixth opossums,respectively. Current usage of the binomenThylamys macrurus dates from Gardner andCreighton (1989).


Names based on Azara’s fourth opossumhave therefore been applied to several zoo-logical species, and key issues of identifica-tion remain unresolved. In particular, thetaxonomic distinctness of Azara’s fourth andsixth opossums has never been effectivelyestablished (see below), so current use ofThylamys macrurus is problematic in theabsence of type material. We therefore select

as neotype of Thylamys macrurus (Olfers,1818) an adult female specimen in theUniversity of Michigan Museum of Zoology(UMMZ 125243), consisting of a skin andskull collected by Thomas W. Nelson (orig-inal number TWN 103) at 28 km SW PedroJuan Caballero (22u349S, 55u379W) in De-partamento Amambay, Paraguay, on 9February 1977. Based on this specimen and

Fig. 3. Map of collecting localities for examined Paraguayan specimens of Thylamys (numberscorrespond to gazetteer entries in the appendix). Some adjacent Brazilian and Bolivian collecting localitiesare also mapped, but not all of those listed in the gazetteer are shown. The locations of Paraguayan townsmentioned in Azara’s opossum accounts are also indicated; coordinates of most of these can be found instandard gazetteers (e.g., Paynter, 1989; DMA, 1992), but the location of Tapua is based on a map inFrakes (1989). That part of Paraguay to the east of the Rıo Paraguay is commonly known as the EasternRegion, and the part to the west is commonly known as the Chaco (Myers, 1982).


other examined material, we provide anemended diagnosis of the species and sum-marize other pertinent information in thetaxonomic accounts below.

The Fifth Opossum

Azara’s micoure a queue courte was thebasis for Didelphys brevicaudis Olfers (1818),a name that was entirely forgotten in thesubsequent systematic literature until redis-covered by Hershkovitz (1959). Didelphis(Monodelphis) wagneri Matschie (1916) is anobjective junior synonym.8 The zoologicaltaxon in question is clearly a species ofMonodelphis, as indicated by Azara’s mea-surements (indicating a very small specieswith a tail much shorter than the combinedlength of the head and body), and hisdescription of its small ears, squat body,short fur, and distinctive coloration (grizzledgrayish brown dorsally with reddish flanks).

Azara’s account of this species in theEssais was based on a specimen obtained byhis friend Pablo Blas Noseda. According toGlick and Quinlan (1975), Noseda was aparish priest at the Jesuit mission settlementof San Ignacio Guazu (5 San Ignacio at26u529S, 57u039W; Paynter, 1989) in Depar-tamento Misiones, Paraguay. In the Apunta-mientos, however, Azara stated that he hadseen specimens from between 27u and 34uSouth latitude; within the geographic limitsof his known itineraries (Mones and Klap-penbach, 1997: apendice V), this additionalmaterial might have come from southernParaguay, northern Argentina, or Uruguay.

Although brevicaudis Olfers, 1818, hasbeen infrequently mentioned in the literature,it is not a nomen oblitum in the technical senseof the International Code of ZoologicalNomenclature (ICZN, 1999; contra Gardner,2005). Therefore, it can be used to replacesubjective junior synonyms in current use, ifany exist. Whether it should be used for thatpurpose is debatable, however, nor is it clear

what currently accepted name(s) might beaffected.

The red-flanked Paraguayan species ofMonodelphis is currently known as M. sorex(Hensel, 1872). According to Pine andHandley (2008), brevicaudis might be a seniorsynonym of sorex, but those authors cautionthat another reddish-flanked species, M.dimidiata (Wagner, 1847), is known fromlocalities not far from Paraguay and mightoccur there too. Such uncertainties couldobviously be resolved by neotype selection,but we have not made a close study of thesetaxa, and it seems irresponsible to take suchaction without having seen all of the relevanttype material. Furthermore, the names sorexand dimidiata are now widely used, and nobiological purpose would be served byreplacing either with brevicaudis. Therefore,another defensible option would be topetition the International Commission onZoological Nomenclature to use its plenarypowers to suppress brevicaudis, which hasonly been used as a valid name by a fewauthors (e.g., Hershkovitz, 1959; Wetzel andLovett, 1974; Brown, 2004). Although thelatter course of action would effectivelyconserve current binomial usage (Gardner,2005; Pine and Handley, 2008), it is possiblethat Paraguayan populations of red-flankedMonodelphis are taxonomically distinct fromother named forms and would then need anew name. Only careful revisionary workbased on first-hand examination of types andother relevant specimens can establish theappropriate action to take in this matter.

The Sixth Opossum

Azara’s micoure nain of the Essais was thebasis for pusilla Desmarest, 1804, anothername that has historically been associatedwith several different didelphid species. Thenames nana Oken, 1816, and nana Olfers,1818, are objective junior synonyms thathave never been used as valid names.

Azara (1801, 1802) introduced his sixthopossum as a new species, one not previouslymentioned by Buffon, Brisson, Linnaeus, orother authors discussed in previous accounts.His description was based on two males, saidto be adults, that were captured by Indiansfrom San Ignacio Guazu (5 San Ignacio at

8 Matschie’s name was proposed as a replacement for‘‘Didelphis brachyura’’ (5 D. brachyuros Schreber, 1778) asmistakenly applied by Wagner (1855) to Azara’s fifth opossum.Wagner’s usage was a misidentification because brachyurosSchreber is an objective junior synonym of brevicaudata,Erxleben, 1777, a distinct species from the Guiana Region ofAmazonia (Voss et al., 2001).


26u529S, 57u039W; Paynter, 1989) in theParaguayan department of Misiones. Amongother characters, this species was said to besmall (his measurements work out to a head-and-body length of about 90 mm with asomewhat longer tail), and to be coloredessentially like the fourth opossum (with ablackish circumocular mask, whitish eye-brows, grayish dorsum, and whitish venter).

Notwithstanding Azara’s reference tograyish dorsal pelage, Thomas (1888) appliedpusilla Desmarest to material in the BritishMuseum representing two different specieswith distinctly reddish fur: Cryptonanusguahybae (Tate, 1931) and Gracilinanusmicrotarsus (Wagner, 1842). Later, Thomas(1900) recognized Marmosa microtarsus(Wagner) and M. pusilla (Desmarest) asdistinct species, but he applied the latterbinomen to the taxon currently known asGracilinanus agilis (Burmeister, 1854). Tate(1933) used M. pusilla for the species ofThylamys previously known as M. citellaThomas (1912), and Desmarest’s name hasbeen used consistently thereafter for one ormore species of Thylamys.

Based on specimens that we examined,there are only two unambiguously distin-guishable species of Thylamys in Paraguay: alarge species in the Eastern Region, and asmall species in the Chaco (fig. 3). Bothspecies are also known from neighboringcountries, but they have never been found insympatry, and their Paraguayan distributionsare separated by the Rıo Paraguay (as arethose of many other mammals; Myers, 1982).As explained above, the large species ofThylamys in the Eastern Region is currentlyknown as T. macrurus, whereas the smallChacoan species is currently known as T.pusillus. The latter usage is now well estab-lished and is, in fact, universally accepted bymodern authors (e.g., Gardner, 1993, 2005;Flores et al., 2000, 2007; Solari, 2003; Braunet al., 2005; Carmignotto and Monfort, 2006;Creighton and Gardner, 2008).

The essential problem, hitherto unad-dressed in the literature, consists in the factthat the type locality of Thylamys pusillus(San Ignacio) is in the Eastern Region,whereas all known Paraguayan specimenscurrently identified as belonging to thisspecies are from the Chaco. Two explana-

tions for this discrepancy suggest themselves.Either (1) Azara’s sixth opossum was not thesame as the species currently known as T.pusillus, or (2) the species currently known asT. pusillus really does occur in the EasternRegion but has yet to be found there bymodern collectors.

The first explanation is plausible becausenothing in Azara’s description is unambigu-ously diagnostic and there is at least onenotable discrepancy. Although Azara’s mea-surements and color descriptors fit thespecies currently known as Thylamys pusillusreasonably well, they are equally applicableto immature specimens of T. macrurus.Because Azara did not examine skulls todetermine dental eruption sequences, there isno way to be sure that his specimens werereally mature (as he believed them to be).Furthermore, T. pusillus has a conspicuouslyincrassate tail (swollen with stored fat),whereas the sixth opossum was said to havea tail that was more slender than that of thefourth opossum (T. macrurus).

The second explanation—that Thylamyspusillus really occurs in the Eastern Regionbut has yet to be collected there—is surelypossible, because the mammalian fauna ofParaguay is still incompletely known. How-ever, existing collection records for thesespecies (mapped in fig. 3) together withzoogeographic expectations from well-docu-mented patterns of regional endemism(Myers, 1982) tend to suggest that, if anyThylamys is eventually collected in thedepartment of Misiones, it is more likely tobe T. macrurus than T. pusillus. Altogether, itseems impossible to convincingly justifycurrent usage of these names based onAzara’s texts.

If Azara’s fourth and sixth opossums werereally the same species, then the appropriatename for the eastern Paraguayan Thylamyscurrently known as T. macrurus is T. pusillus,and the small Chacoan species should beknown by one of the names currently treatedas subjective junior synonyms of the latter(e.g., verax Thomas, 1921). Needless to say,such changes would destabilize current no-menclature, and they would serve no usefulbiological purpose. We therefore select asneotype of Thylamys pusillus (Desmarest,1804) an adult male specimen in the Museum


of Vertebrate Zoology (MVZ 144311), con-sisting of a skin and skull collected by PhilipMyers (original number 800) near the Trans-Chaco highway 460 km NW of Villa Hayesin Departamento Boqueron, Paraguay, on 7April 1973. Based on this specimen and otherexamined material, we provide an emendeddiagnosis of the species and summarize otherpertinent information in the taxonomicaccounts below.

SPECIES ACCOUNTS

Based on the neotypes designated aboveand other examined material, we here sum-marize relevant taxonomic informationabout Thylamys macrurus and T. pusillus,including type localities, known distributions,emended diagnoses, brief comparisons withother congeneric forms, and remarks aboutproblems that we encountered in attemptingto identify museum specimens, allocate pu-tative synonyms, etc.

Thylamys macrurus (Olfers, 1818)

NEOTYPE: Skin and skull of an adultfemale in the University of Michigan Muse-um of Zoology (UMMZ 125243) collected byThomas W. Nelson (original number TWN103) on 9 February 1997.

TYPE LOCALITY: Twenty-eight kilometersSW Pedro Juan Caballero, DepartmentoAmambay, Paraguay. Although this locality(copied from the field label tied to the skin ofUMMZ 125243) appears to be on privateland according to modern satellite imagery,the collector of the neotype (and two juvenilespecimens with the same locality data)recently told us that all of his trapping nearPedro Juan Caballero was done within theboundaries of Parque Nacional Cerro Cora,which lies about 12 km to the NW. Accord-ing to this source (T.W. Nelson, personalcommun.), local habitats consisted of forestthat ‘‘had a mostly closed, at least medium-tall canopy with some large trees, along withsome open agricultural areas that werestarting to return to forest.’’ The area was‘‘definitely not savanna-like, but certainly notundisturbed primary forest either.’’ Thisrecollection is supported by taxonomic iden-tifications of small mammals collected at the

same locality, which include both moist-forest and open-country species: Monodelphisdomestica, Dasypus novemcinctus, Artibeuslituratus, Glossophaga soricina, Myotis nigri-cans, Cebus libidinosus, Mazama americana,Thrichomys pachyurus, Akodon montensis,Nectomys squamipes, Oligoryzomys nigripes,Hylaeamys megacephalus, and Cerradomysmaracajuensis. Other species collected withinthe park’s boundaries include Didelphisalbiventris, Marmosa (Micoureus) constan-tiae, Carollia perspicillata, Sturnira lilium,Platyrrhinus lineatus, Eptesicus furinalis, andSooretamys angouya.

DISTRIBUTION: Based on specimens thatwe examined and other captures reported byCaceres et al. (2007), Thylamys macrurusappears to be restricted to Mato Grosso doSul (Brazil) and the Eastern Region ofParaguay. A single Bolivian locality reportedby Anderson (1997) and an Argentinianlocality mapped by Brown (2004) are bothbased on misidentifications. The Bolivianspecimen in question (AMNH 263549) is anexample of Marmosops ocellatus (see Voss etal., 2004: 31), and the Argentinian specimen(BMNH 98.8.19.9) is the holotype of Mar-mosa citella (possibly a subjective synonym ofT. pusillus; see below).

There exist substantive discrepancies be-tween Paraguayan and Brazilian habitatswhere Thylamys macrurus has been collected.At both the type locality (described above)and at 7 km NE Concepcion (where EduardoPalma collected a fourth Paraguayan speci-men; appendix 2: locality 25), the dominantnatural habitat consisted of tall subtropicalmoist (semi-evergreen) forest. Due to humanintervention, this habitat is currently inter-spersed, throughout eastern Paraguay, withagricultural fields, regenerating secondarygrowth, and pastures. Similar conditionsalmost certainly occurred in the 19th centurynear Asuncion (where N.L. Holden collecteda fifth Paraguayan specimen; appendix 2:locality 23), and near Sapucay (where W.Foster collected a sixth example; appendix 2:locality 28).

By contrast, Brazilian captures of Thyla-mys macrurus are all from the Cerrado(Eiten, 1972, 1978), a vast mosaic of xer-omorphic vegetation types ranging fromtreeless savanna (campo limpo) to open


woodlands (campo cerrado) and deciduousforests (cerradao). Within this landscape,Thylamys macrurus appears to be mostconsistently associated with open woodlandsand deciduous forests (Carmignotto andMonfort, 2006; Caceres et al., 2007), habitatsthat do not resemble any intact vegetationformations that we have seen in easternParaguay. We showed photographs of Cer-rado habitats in which Brazilian specimens ofT. macrurus were trapped to T.W. Nelson(collector of the neotype, see above), whoemphatically stated that it was unlike thesecondary moist forest in which he trappedT. macrurus near Pedro Juan Caballero.

EMENDED DIAGNOSIS: Thylamys macrurusis distinctively larger in most measureddimensions (table 2) than other congenericspecies, from which it also differs in qualita-tive external and craniodental traits. The tailis distinctly longer (by about 22%) than thecombined length of the head and body.Although the presence of caudal subcutane-ous fat is less externally evident than in othercongeneric species, the tail of T. macrurus(fig. 4) is still visibly incrassate (contraPalma, 1995, 1997; Creighton and Gardner,2008). The tail is bicolored proximally (darkabove, whitish below), but the terminal one-

fifth to one-third is entirely white. Theventral surface of the tail is modified forprehension distally, with a naked mediangroove and a fleshy apical pad bearingdermatoglyphs. The body pelage is distinctlytricolored (sensu Tate, 1933: 209), with adark grayish or grayish-brown middorsalregion, paler flanks, and sharply definedventral countershading. The dorsal fur isshort (usually 8–9 mm long middorsally),and the ventral fur is mostly self-white or-cream from chin to anus; however, a narrowlateral zone of gray-based hairs is usuallypresent. The manual claws are short (not, oronly slightly extending beyond the fleshyapical pad of each digit), and the ventralsurface of the manus has six separatedermatoglyph-bearing plantar pads encir-cling a concave, densely tubercular centralpalmar region. The supraorbital margins areindistinctly beaded in large specimens, someof which (e.g., MZUSP 32094) have indistinctpostorbital processes. The zygomatic archesare wide relative to cranial length (theaverage ratio of zygomatic breadth to con-dylobasal length expressed as a percentage[ZB/CBL 3 100] is about 56%). Distinctmaxillary palatal vacuities are invariablypresent, although these openings are some-

TABLE 2Measurements (mm) and Weights (g) of Subadult and Adult Specimens of Thylamys macrurus

BMNH BMNH MSB MZUSP MZUSP MZUSP UMMZ MZUSP

99.11.17.1 3.4.7.21 70700 32094 32095 32096 125243a 3782

Age subadult adult adult adult adult adult adult adult

Sex male female female female female female female male

HBL — 147b 130 126 108 106 135 110

LT — 161b 154 153 143 138 140 132

HF — 15b 18 19 16 17 17 —

Ear — 25b 23 27 23 24 25 —

CBL 29.2 33.3 33.4 32.5 29.9 29.6 34.2 31.9

NB 2.8 2.9 3.4 3.5 2.8 2.5 2.9 2.6

LIB 4.6 5.4 5.2 5.3 4.9 4.3 5.4 4.7

ZB 16.9 18.9 18.3 19.2 17.0 16.0 19.2 17.8

PL 16.2 18.2 17.9 17.1 16.4 15.8 18.6 17.7

PB — 11.0 10.4 10.4 9.5 9.4 10.9 10.1

MTR 12.1 12.8 12.6 12.1 11.9 12.1 12.9 12.4

LM 6.6 6.4 6.3 6.4 6.1 6.5 6.5 6.4

M1–3 5.8 5.4 5.4 5.5 5.3 5.6 5.4 5.5

Weight — — 57 55 30 31 54 —

a Neotype.b Measurement method unknown, but probably not following the standard American protocol.


times small. The posterolateral palatal foram-ina usually extend anteriorly to a point that islingual to the M4 protocones, but they are notas long as in most other congeneric species(Carmignotto and Monfort, 2006: fig. 6). Theauditory bullae are relatively small, the dis-tance between the left and right bullae greatlyexceeding the width of either bulla. Stylar cuspC is consistently present on M1–M3.

COMPARISONS: The known geographicrange of Thylamys macrurus is adjacent tothe distributions of three congeneric species,with which it merits brief comparisons. Thesmaller Brazilian species T. karimii and T.velutinus differ from T. macrurus (amongother characters) by having longer claws thatextend well beyond the fleshy apical pads ofthe manual digits; manual plantar pads arefused together and do not surround a centralpalmar concavity; a tail that is substantiallyshorter than the combined length of head andbody; no prehensile modifications on theunderside of the tail tip; indistinctly tricol-ored body pelage; and much longer postero-lateral palatal foramina (see illustrations in

Carmignotto and Monfort, 2006). Bothspecies occur in Cerrado (T. velutinus) orCerrado and Caatinga (T. karimii) land-scapes that are drier and more seasonal thanthose inhabited by T. macrurus in easternParaguay and Mato Grosso do Sul.

Thylamys pusillus, the only other species ofThylamys known to occur in Paraguay,differs from T. macrurus by being substan-tially smaller (with nonoverlapping molardimensions; tables 2, 3), by lacking a pale tailtip, by its entirely self-white ventral fur(lacking lateral zones of gray-based hairs),by having much longer posterolateral palatalforamina, and by usually lacking styC onM3. Based on specimens that we examined(fig. 3), the ranges of T. pusillus and T.macrurus are separated by the Rıo Paraguayand by the seasonally innundated pantanales(palm savannas) of the eastern Chaco.

SPECIMENS EXAMINED: Brazil—MatoGrosso do Sul, Campo Grande (MZUSP3782), Fazenda California (MZUSP 32094–32096), Fazenda Santa Terezinha (MZUSP32097). Paraguay—Amambay, 28 km SW

Fig. 4. Thylamys macrurus in life (MZUSP 32094), photographed at Fazenda California, Mato Grossodo Sul, Brazil, by A.P. Carmignotto.


Pedro Juan Caballero (UMMZ 125243,125259, 125260); Central, Asuncion (BMNH99.11.17.1); Concepcion, 7 km NE Concep-cion (MSB 70700); Paraguarı, Sapucay(BMNH 3.4.7.21).

Thylamys pusillus (Desmarest, 1804)

NEOTYPE: Skin and skull of an adult malein the Museum of Vertebrate Zoology at theUniversity of California Berkeley (MVZ144311) collected by Philip Myers (originalnumber PM 800) on 7 April 1973.

TYPE LOCALITY: On the Trans-Chacohighway 460 km NW of Villa Hayes, inDepartamento Boqueron, Paraguay. Theneotype was trapped on the ground in dense,thorny vegetation that included quebracho(Schinopsis sp. and/or Aspidosperma quebra-cho-blanco), palo santo (Bulnesia sarmientoi),palo borracho (Chorisia insignis), and severalspecies of cacti; however, a small, apparentlynatural grassy opening was also adjacent tothe trap site.

DISTRIBUTION: Specimens that we exam-ined document the presence of Thylamyspusillus only in the Chaco Boreal of western

Paraguay and southeastern Bolivia. Withexceptions as noted below, specimens previ-ously reported in the literature as T. pusillusthat we examined from other regions provedto be misidentified. Records of T. pusillusfrom the Bolivian highlands (e.g., most of thematerial that Anderson [1997] listed fromChuquisaca), for example, are based on T.venustus, whereas Brazilian records (e.g.,those mapped by Brown [2004] are basedon T. karimii, and Patagonian records (e.g.,those reported by Birney et al., 1996) arebased on T. pallidior. Although T. pusillusmight occur in the Chaco Austral of northernArgentina (Flores et al., 2000, 2007), thespecimens that we examined from that regiondiffer morphologically from Paraguayan andBolivian material and might represent yetanother species (see below).

Thylamys pusillus is found in xerophyticwoodlands that are dominated by low(usually ,15 m), thorny, deciduous treesincluding quebracho, palo santo, palo borra-cho, and labon (Tabebuia nodosa). Theunderstory typically includes algarrobo (Pro-sopis spp.), Maytenus spp., Mimosa spp.,

TABLE 3Measurements (mm) and Weights (g) of Adult Specimens of Thylamys pusillus

Neotypeb

Sample statisticsa

Femalesc Malesd

HBL 101 99 6 11 (85–117) 14 101 6 10 (81–114) 16

LT 104 114 6 12 (92–131) 14 117 6 9 (104–134) 16

HF 13 14 6 2 (11–19) 15 14 6 1 (12–16) 16

Ear 20 21 6 2 (18–24) 15 21 6 2 (18–25) 16

CBL 26.1 26.5 6 1.2 (24.4–28.9) 15 26.6 6 1.0 (25.4–28.5) 18

NB 2.2 2.4 6 0.3 (2.0–3.1) 15 2.3 6 0.3 (1.6–2.7) 18

LIB 3.8 4.1 6 0.2 (3.6–4.5) 15 4.0 6 0.2 (3.7–4.2) 18

ZB 14.8 15.2 6 0.9 (14.1–16.7) 14 15.0 6 0.6 (13.9–16.1) 18

PL 14.0 14.2 6 0.6 (13.4–15.4) 15 14.3 6 0.5 (13.6–15.3) 18

PB 8.0 8.6 6 0.3 (7.9–9.1) 15 8.5 6 0.3 (8.0–9.1) 18

MTR 10.2 10.2 6 0.4 (9.6–10.9) 15 10.3 6 0.3 (10.0–11.2) 18

LM 5.2 5.4 6 0.2 (5.0–5.6) 15 5.4 6 0.2 (5.2–5.8) 18

M1–3 4.5 4.6 6 0.2 (4.3–4.9) 15 4.6 6 0.2 (4.4–5.1) 18

Weight 20 21 6 6 (14–31) 15 22 6 5 (11–31) 16

a Tabulated statistics include the sample mean plus or minus one standard deviation, the observed range (in

parentheses), and the sample size.b MVZ 144311, male.c AMNH 260025, 275442; FMNH 164086, 164097; MSB 67016, 87105; TK 63360, 65215, 65458, 65463, 65592, 65601,

66463, 66468; UMMZ 176357.d AMNH 246444, 246446, 275440, 275445, 275446; FMNH 164088, 164096; MVZ 144311, 144312; TK 60217, 60227,

63367, 65612, 66469, 66476; TWN 240, 275; UMMZ 124676.


Ephedra spp., and several species of cacti.Dense patches of spiny bromeliads (cara-guata: Bromelia hieronymi, B. serra) providegroundcover that is nearly impenetrable tomammalian or avian predators. Short (1975:173) referred to these forests as ‘‘dry (Algar-robo-Quebracho-Palo Santo) woodlands’’and provided a detailed description andphotographs of this uniquely Chacoan hab-itat.

EMENDED DIAGNOSIS: Thylamys pusillusexhibits a distinctive range of morphometricvariation (table 3) and differs from othercongeneric species in many qualitative traits.The tail, consistently longer than the com-bined length of the head and body (by about14–16%), is distinctly incrassate, sharplybicolored (dark above, whitish below), andthe ventral surface is modified for prehensiondistally (with a naked median groove and afleshy apical pad bearing dermatoglyphs).The body pelage is distinctly tricolored(sensu Tate [1933: 209]), with a dark grayishor brownish-gray middorsal region, palerflanks, and sharply defined ventral counter-shading. The dorsal fur is short (usually 7–8 mm long middorsally), and the ventral furis entirely self-white or -cream (not graybased) from chin to anus. The manual clawsare short (not, or only slightly extendingbeyond the fleshy apical pad of each digit),and the ventral surface of the manus has sixseparate dermatoglyph-bearing plantar padsencircling a concave, densely tubercularcentral palmar region. The zygomatic archesare wide relative to cranial length (theaverage ratio of zygomatic breadth to con-dylobasal length 3 100 is about 55%–56%);distinct maxillary palatal vacuities are almostalways present; the posterolateral palatalforamina are very long (extending wellanterior to the protocone of M4 on eachside); the auditory bullae are relatively smallby comparison with those of other species;and styC is usually present on M1 and M2,but it is usually absent from M3.

COMPARISONS: Diagnostic comparisons ofThylamys pusillus with T. macrurus havealready been discussed. The Brazilian speciesT. karimii (synonymized with T. pusillus byGardner, 1993) is craniodentally similar butdiffers from T. pusillus by having longer clawsthat extend well beyond the fleshy apical pads

of the manual digits; manual plantar padsthat are fused together, lack dermatoglyphs,and do not surround a central palmarconcavity; a tail that is substantially shorterthan the combined length of head and body;no prehensile modifications on the undersideof the tail tip; and indistinctly tricolored bodypelage (see illustrations in Carmignotto andMonfort, 2006). Geographically, T. karimii isendemic to the Cerrado and Caatinga biomesnorth and east of the Chacoan regioninhabited by T. pusillus.

Thylamys pallidior (treated as a subspeciesof T. pusillus by Cabrera, 1958) differsexternally from T. pusillus by its much longerfur (usually .10 mm middorsally) and longermanual claws (which always extend beyondthe fleshy apical pad of each digit). Cranially,T. pallidior differs from T. pusillus by itslonger and more slender rostrum, narrowerzygomatic arches, much larger bullae, and bythe consistent absence of maxillary fenestrae(fig. 5). A diagnostic dental difference con-sists in the absence of stylar cusp C from M1–M3 in T. pallidior, whereas styC is consis-tently present on M1 and M2 in T. pusillus.Based on material that we examined, Thyla-mys pallidior (which may represent a complexof two or more morphologically similarspecies; Braun et al., 2005) occurs fromsouth-central Peru (on the west side of theAndes; Solari, 2003) across the Bolivianhighlands into northwestern and PatagonianArgentina; apparently, it occupies a widerange of arid habitats including Puna grass-lands, Monte desert, and Patagonian steppe(Flores et al., 2000, 2007).

REMARKS: The only subjective juniorsynonym of Thylamys pusillus that we canconfidently recognize as such is Marmosaverax Thomas (1921), the holotype of which(BMNH 20.12.18.34) is a very old adultfemale with stained (yellowish) ventral furfrom ‘‘Mision, west of Concepcion,’’ alocality said to be in the Paraguayan Chaco(Thomas, 1921: 521), but one that we havebeen unable to associate with definite geo-graphic coordinates.9 Apart from its ad-vanced age (and correspondingly large mea-

9 A plausible candidate, however, is Mision Central(23u279S, 58u209W; DMA, 1992), about 90 km due west ofConcepcion in Presidente Hayes department.


Fig. 5. Dorsal and ventral cranial views of Thylamys pusillus (A, C; AMNH 275445) and T. pallidior(B, D; AMNH 262408) illustrating diagnostic qualitative cranial characters mentioned in the text.


surements; e.g., CBL 5 29.8 mm), thisspecimen does not differ in any respect fromother material that we refer to T. pusillus.

Marmosa citella Thomas (1912) has beenconsidered a junior synonym of Thylamyspusillus by most authors (e.g., Tate, 1933;Cabrera, 1958; Creighton and Gardner,2008), and this opinion may be correct.However, our cursory examination of theholotype (BMNH 98.8.19.9) during a briefvisit to London that was primarily devoted toanother project did not allow us to come to adefinite conclusion, nor do our notes containinformation about several key characters(such as the presence or absence of styC onthe upper molars). The chief difficulty inadmitting this synonymy is that the typelocality of citella (Goya, at 29u089S, 59u169W;Paynter, 1995) in the Argentine province ofCorrientes is so distant from any others fromwhich we have seen similar material.

Although specimens resembling Thylamyspusillus have been taken across much ofnorthern Argentina (in the provinces ofChaco, Entre Rıos, Formosa, Santiago delEstero, Salta, and Tucuman; Flores et al.,2000, 2007), most of the pusillus-like Argen-tinian material that we examined is substan-tially smaller (e.g., with LM , 5 mm) thanthe western Paraguayan and southeasternBolivian specimens that we consider torepresent typical pusillus. In addition, styCis more consistently distinct on M3 inpusillus-like Argentinian specimens than it isin Paraguayan and Bolivian material. Amongthe small, pusillus-like Argentinian specimenswe examined is BMNH 21.4.21.8, the sub-adult male holotype of Marmosa bruchi,which Thomas (1921) described from AltoPencoso (33u269S, 66u569W; Paynter, 1995) inwestern San Luis province. Although bruchiis currently considered a synonym of T.pallidior (e.g., by Gardner, 2005; Creightonand Gardner, 2008), its short fur, distinctmaxillary vacuities, and well-developed styCon M1 and M2 better match the diagnostictraits of T. pusillus as recognized here. Thename pulchellus Cabrera (1934a) may be ajunior synonym of bruchi (as suggested byCabrera, 1958), but we have not seen theholotype.

Interestingly, Braun et al. (2005) foundthat cytochrome-b sequences from Argenti-

nian specimens of ‘‘pusillus’’ were about 3%divergent from a single Paraguayan se-quence in their phylogenetic analysis of thegenus Thylamys. We examined their vouchermaterial and found that the Paraguayanspecimen (with field number TK 66469) is atypical example of pusillus, whereas theirpusillus-like Argentinian material (e.g.,AK14628 [5 OMNH 23483] and OMNH23479) more closely resembles bruchi in sizeand dental morphology. Although we areencouraged to think that bruchi may be avalid species of Thylamys, closely related tobut phenotypically and genetically distinctfrom T. pusillus, it remains for futureresearchers to determine whether there is agradual or abrupt morphological transitionfrom the small Argentinian phenotype to thelarger Paraguayan-Bolivian phenotype, andto discover whether specimens sorted by sizeform reciprocally monophyletic haplotypegroups.

SPECIMENS EXAMINED: Bolivia—Chuqui-saca, 3.8 km by road E Carandayti (AMNH261268); Santa Cruz, 53 km E of Boyuibe(AMNH 275441; MSB 87105), Tita (AMNH260025); Tarija, Estancia Bolıvar (AMNH275440, 275442, 275445, 275446; MSB67016), 8 km S [and] 10 km E Villa Montes(AMNH 246442–246444, 246446–246449,246452). Paraguay—Alto Paraguay, Desta-camento Militar Gabino Mendoza (TTU-TK65601, 65632, 65635), Fortın Pikyrenda(TTU-TK 65592, 65612), Palmar de las Islas(TTU-TK 65458, 65463); Boqueron, Estancia‘‘El 43’’ (TTU-TK 60217, 60227), EstanciaToledo (FMNH 164097), ExperimentalFarm (FMNH 164095, 164096), Guachalla(FMNH 54369), Orloff (FMNH 63862),Parque Cue (TTU-TK 63360, 63367), ParqueNacional Teniente Agripino Enciso (TTU-TK 65031, 65104, 65215, 66463, 66468,66469, 66476), Schmidt Ranch (FMNH164086), 410 km NW Villa Hayes (MVZ144312, 144313), 460 km NW Villa Hayes(MVZ 144311); Chaco, 50 km WNW FortınMadrejon (UMMZ 124676); Nueva Asuncion,1 km SW km 620 [of] Trans-Chaco Road(UMMZ 176357); 19 km by road WSWkm 588 [of] Trans-Chaco Road (UMMZ176358, TWN 240, 275, 390). PresidenteHayes, 295 km NW Villa Hayes (MVZ144310).


DISCUSSION

There are many reasons why the system-atics of South American mammals are still sopoorly understood. Among others, the con-tinental fauna remains incompletely invento-ried; the geographic, morphological, andgenetic limits of numerous species are stillundocumented; and the taxonomic applica-tion of many old names is a persistent sourceof confusion. In the absence of survivingoriginal material (holotypes, syntypes, etc.),the last problem has often been addressed byrestricting the type locality (as by Thomas,1911; Cabrera, 1958) and examining ‘‘topo-types,’’ but neither of these conventions,however useful they might be in practice,have any binding nomenclatural significanceunder the International Code of ZoologicalNomenclature (ICZN, 1999). A better op-tion, when it is necessary to fix the applica-tion of names, and when the consequences offailing to doing so are dire, is the designationof neotypes. Like sharp-edged tools, howev-er, neotypes are potent instruments thatshould be used with care.

This report on Azara’s opossums wasprompted by ongoing revisionary researchwith South American didelphids, the nomen-clature of which is not uniquely problematic.Indeed, other groups of mammals described byAzara also merit critical review and remedialaction as necessary to stabilize taxonomicusage. Although some problems associatedwith Azara’s rats have now been resolved(Tate, 1932; Myers and Carleton, 1981; Musseret al., 1998), others persist. For example, theambiguous application of Oxymycterus rufusFischer, 1814, is unlikely ever to be resolvedwithout a neotype (Hershkovitz, 1994; Oli-veira, 1998; Musser and Carleton, 2005;Goncalves and Oliveira, 2004). Other groupshave received little critical attention.

The only general introduction to Azara’smammals (Hershkovitz, 1987) was writtenmore than 20 years ago and containsnoteworthy errors that should be correctedin any future taxonomic assessment of thisauthor. Inter alia, the basis for Coendouinsidiosus (Olfers, 1818) was not Azara’s(1801) description of ‘‘Le Couiy’’ but anexamined specimen in the Berlin ZoologicalMuseum (Voss and Angermann, 1997). Also,

the basis for some of the Paraguayan batsdescribed by Geoffroy (1810), includingPlatyrrhinus lineatus and Sturnira lilium, iscontroversial: whereas Hershkovitz (1987)claimed that these binomens were based onAzara’s (1801) text, other authors (e.g.,Rode, 1941; Carter and Dolan, 1978; San-chez-Hernandez and Romero-Almaraz, 2003;Velasco, 2005) have alleged that type material(not collected by Azara according to Cab-rera, 1958) is present in the Museum Nation-al d’Histoire Naturelle (Paris). In effect, morebibliographic and specimen-based research isneeded before Azara’s mammalogical legacycan be accurately evaluated.

ACKNOWLEDGMENTS

Among many other persons who helped uswith this project, we especially thank PatBrunauer (AMNH Department of Mammal-ogy) and Ingrid Lennon (AMNH Depart-ment of Library Services) for indispensibleassistance in tracking down rare and obscurereferences; Eileen Westwig (AMNH Depart-ment of Mammalogy) for efficiently process-ing a seemingly endless series of specimenloans; Neil Duncan (AMNH OsteologicalPreparation Laboratory) for expertly clean-ing numerous important specimens; TeresaPacheco (AMNH Department of Mammal-ogy) for periodic assistance with our transla-tions from the Apuntamientos; and Patricia J.Wynne for her painstaking pen-and-inkillustrations. We are also grateful to thosewho loaned us crucial specimens for thisproject, especially Robert Owen, who gener-ously shared unpublished material collectedby his research teams throughout Paraguay.Other important loans were made possible byJanet Braun (OMNH); Chris Conroy, EileenLacey, and Jim Patton (MVZ); Jon Dunnumand Joe Cook (MSB); Linda Gordon(USNM) and Al Gardner (U.S. GeologicalSurvey); Bruce Patterson (FMNH); andMario de Vivo (MZUSP). David Florescontributed useful information about Argen-tinian specimens that we were not able toexamine, and Nuria Garcia provided techni-cal assistance in Madrid. For critical com-ments on an early draft of this report, wethank J.K. Braun, M.D. Carleton, D.A.Flores, A.L. Gardner, and G.M. Martin.


REFERENCES

Allen, J.A. 1902. A preliminary study of the SouthAmerican opossums of the genus Didelphis.Bulletin of the American Museum of NaturalHistory 16 (20): 249–279.

Anderson, S. 1997. Mammals of Bolivia, taxono-my and distribution. Bulletin of the AmericanMuseum of Natural History 231: 1–652.

Azara, F. de. 1801. Essais sur l’histoire naturelledes quadrupedes de la province du Paraguay.Paris: Charles Pougens, 2 vols.

Azara, F. de. 1802. Apuntamientos para la historianatural de los quadrupedos del Paraguay y Rıode la Plata. Madrid: Imprenta de la Viuda deIbarra, 2 vols. [Reprinted in the series ‘‘Biolo-gists and their world’’ in 1978 by Arno Press,New York.]

Azara, F. de. 1809. Voyages dans l’Ameriquemeridionale, depuis 1781 jusqu’en 1801 [etc].Paris: Dentu, 4 vols. + atlas.

Azara, F. de. 1904. Geografıa fısica y esferica delas provincias del Paraguay, y misiones gura-nıes. [Posthumously published from a manu-script edited by R.R. Schuller.] Anales delMuseo Nacional de Historia Natural de Mon-tevideo (Seccion Historico-Filosofico) 1: i–cxx-vii, 1–478.

Beddall, B.G. 1975. ‘‘Un naturalista original’’:Don Felix de Azara, 1746–1821. Journal of theHistory of Biology 8: 15–66.

Birney, E.C., R.S. Sikes, J.A. Monjeau, N.Guthmann, and C.J. Phillips. 1996. Commentson Patagonian marsupials from Argentina. InH.H. Genoways and R.J. Baker (editors),Contributions in mammalogy: a memorial vol-ume honoring Dr. J. Knox Jones, Jr.: 150–154.Lubbock: Museum of Texas Tech University.

Braun, J.K., R.A. Van den Bussche, P.K. Morton,and M.A. Mares. 2005. Phylogenetic andbiogeographic relationships of mouse opossumsThylamys (Didelphimorphia, Didelphidae) insouthern South America. Journal of Mammal-ogy 86: 147–159.

Brown, B.E. 2004. Atlas of New World marsupi-als. Fieldiana Zoology New Series 102: i–viii, 1–308.

Cabrera, A. 1916. El tipo de Philander lanigerDesm. en el Museo de Ciencias Naturales deMadrid. Boletın de la Real Sociedad Espanolade Historia Natural 16: 514–517.

Cabrera, A. 1934a. Dos nuevos micromamıferosdel norte argentino. Notas Preliminares delMuseo de La Plata 3: 123–128.

Cabrera, A. 1934b. Los envıos de Felix de Azara alReal Gabinete de Historia Natural de Madrid.Anales de la Sociedad Espanola para el Pro-gresso de las Ciencias 1: 98–100.

Cabrera, A. 1958 [1957]. Catalogo de los mamı-feros de America del Sur [pt. 1]. Revista delMuseo Argentino de Ciencias Naturales ‘‘Ber-nardino Rivadavia’’ (Ciencias Zoologicas) 4:1–307.

Caceres, N.C., R.P. Napoli, W.H. Lopes, J.Casella, and G.S. Gazeta. 2007. Natural historyof the marsupial Thylamys macrurus (Mamma-lia, Didelphidae) in fragments of savannah insouthwestern Brazil. Journal of Natural History41: 1979–1988.

Carmignotto, A.P., and T. Monfort. 2006. Tax-onomy and distribution of the Brazilian speciesof Thylamys (Didelphimorphia: Didelphidae).Mammalia 2006: 126–144.

Carter, D.C., and P.G. Dolan. 1978. Catalogue oftype specimens of Neotropical bats in selectedEuropean museums. Special Publications of theMuseum Texas Tech University 15: 1–136.

Cerqueira, R., and C.J. Tribe. 2008. GenusDidelphis Linnaeus, 1758. In A.L. Gardner(editor), Mammals of South America. Vol. 1.Marsupialia, Insectivora, Edentata, Chiroptera:17–25. Chicago: Chicago University Press.

Clemens, W.A., Jr. 1966. Fossil mammals of thetype Lance Formation Wyoming. Part II.Marsupialia. University of California Publica-tions in Geological Sciences 62: i–vi, 1–122.

Creighton, G.K., and A.L. Gardner. 2008. GenusThylamys Gray, 1843. In A.L. Gardner (editor),Mammals of South America. Vol. 1. Marsupi-alia, Insectivora, Edentata, Chiroptera: 107–117. Chicago: Chicago University Press.

Darton, M., and J.O.E. Clark. 1994. The Dentdictionary of measurement. London: J.M. Dent.

Delibes, J., and A. Garcıa-Valdecasas. 1987.Museo Nacional de Ciencias Naturales, Spain:specimens of historical significance. In H.H.Genoways, C. Jones, and O.L. Rossolimo(editors), Mammal collection management:179–184. Lubbock: Texas Tech UniversityPress.

Desmarest, A.G. 1804. Tableau methodique desmammiferes [not seen]. In Nouveau dictionnaired’histoire naturelle, appliquee aux arts, princi-palement a l’agriculture, a l’economie rurale etdomestique. Vol. 24: 5–38. Paris: Deterville.

Desmarest, A.G. 1820. Mammalogie ou descrip-tion des especes de mammiferes. Premier partie,contenant les ordres des bimanes, des quad-rumanes et des carnassiers. Paris: Veuve Agasse.

Desmarest, A.G. 1827. Sarigue [encyclopediaentry]. In Dictionnnaire des sciences naturelles,dans lequel on traite methodiquement desdifferens etres de la nature, consideres soit eneux-memes, d’apres l’etat actuel de nos con-noissances, soit relativement a l’utilite qu’enpeuvent retirer la medecine, l’agriculture, le


commerce et les arts, vol. 47: 377–400. Stras-bourg: Levrault.

Desmoulins, A. 1824. Didelphe [encyclopediaentry]. In J.B.G.M. Bory de Saint-Vincent(editor), Dictionnaire classique d’histoire natur-elle, vol. 5: 485–494. Paris: Rey et Gravier.

DMA, 1824. Gazetteer of Paraguay. 2nd ed.Washington, DC: Defense Mapping Agency.

Eiten, G. 1972. The Cerrado vegetation of Brazil.Botanical Review 38: 201–341.

Eiten, G. 1978. Delimitation of the Cerradoconcept. Vegetatio 36: 169–178.

Engel, H. 1937. The life of Albert Seba. SvenskaLinne-Sallskapets Arsskrift 20: 75–100.

Flores, D.A., M.M. Dıaz, and R.M. Barquez.2000. Mouse opossums (Didelphimorphia, Di-delphidae) of northwestern Argentina: system-atics and distribution. Zeitschrift fur Saugetier-kunde 65: 321–339.

Flores, D.A., M.M. Dıaz, and R.M. Barquez.2007. Systematics and distribution of marsupialsin Argentina: a review. University of CaliforniaPublications in Zoology 134: 579–669.

Frakes, M.A. 1989. Governor Ribera and the Warof the Oranges on Paraguay’s frontiers. TheAmericas 45: 489–508.

Gardner, A.L. 1993. Order Didelphimorphia. InD.E. Wilson and D.M. Reeder (editors), Mam-mal species of the world, a taxonomic andgeographic reference. 2nd ed.: 15–23. Washing-ton, DC: Smithsonian Institution Press.

Gardner, A.L. 2005. Order Didelphimorphia. InD.E. Wilson and D.M. Reeder (editors), Mam-mal species of the world, a taxonomic andgeographic reference. 3rd ed.: 3–18. Baltimore,MD: Johns Hopkins University Press.

Gardner, A.L. 2008. Mammals of South America.Vol. 1. Marsupialia, Insectivora, Edentata, Chi-roptera. Chicago: Chicago University Press.

Gardner, A.L., and G.K. Creighton. 1989. A newgeneric name for Tate’s (1933) MicrotarsusGroup of South American mouse opossums(Marsupialia: Didelphidae). Proceedings of theBiological Society of Washington 102: 3–7.

Geoffroy St.-Hilaire, E. 1810. Sur les phyllos-tomes et les megadermes, deux genres de lafamille des chauve-souris. Annales du MuseumNational d’Histoire Naturelle 15: 157–198 + pls.ix–xii.

Ghiselin, M.T. 1995. Ostensive definitions of thenames of species and clades. Biology andPhilosophy 10: 219–222.

Glick, T.F., and D.M. Quinlan. 1975. Felix deAzara: the myth of the isolated genius inSpanish science. Journal of the History ofBiology 8: 67–83.

Goncalves, P.R., and J.A. de Oliveira. 2004.Morphological and genetic variation between

two sympatric forms of Oxymycterus (Rodentia:Sigmodontinae): an evaluation of hypotheses ofdifferentiation within the genus. Journal ofMammalogy 85: 148–161.

Hall, E.R. 1981. Mammals of North America. 2nded., vol. 2. New York: Wiley.

Hershkovitz, P. 1949. Status of names creditedto Oken, 1816. Journal of Mammalogy 30: 289–301.

Hershkovitz, P. 1959. Nomenclature and taxono-my of the Neotropical mammals described byOlfers, 1818. Journal of Mammalogy 40:337–353.

Hershkovitz, P. 1969. The Recent mammals of theNeotropical region: a zoogeographic and eco-logical review. Quarterly Review of Biology 44:1–70.

Hershkovitz, P. 1987. A history of the Recentmammalogy of the Neotropical region from1492 to 1850. Fieldiana Zoology New Series 39:11–98.

Hershkovitz. 1994. The description of a newspecies of South American hocicudo, or long-nosed mouse, genus Oxymycterus (Sigmodonti-nae, Muroidea), with a critical review of thegeneric content. Fieldiana Zoology New Series79: i–vi, 1–43.

ICZN, 1956. Opinion 417. Rejection for nomen-clatural purposes of volume 3 (Zoologie) of thework by Lorenz Oken entitled Okens Lehrbuchder Naturgeschichte published in 1815–1816.Opinions and declarations rendered by theInternational Commission on Zoological No-menclature 14: 1–42.

ICZN, 1999. International code of zoologicalnomenclature, 4th ed. London: InternationalTrust for Zoological Nomenclature.

ICZN, 2006. Opinion 2164: Didelphis Linnaeus,1758 (Mammalia, Didelphidae): gender correct-ed to feminine, and Cryptotis Pomel, 1848(Mammalia, Soricidae): gender fixed as mascu-line. Bulletin of Zoological Nomenclature 63:282–283.

Kirsch, J.A.W., and J.H. Calaby. 1977. The speciesof living marsupials: an annotated list. In B.Stonehouse and G. Gilmore (editors), Thebiology of marsupials: 9–26. Baltimore, MD:University Park Press.

Larranaga, D.A. 1923. Escritos de don DamasoAntonio Larranaga, vol. 2. Montevideo: Im-prenta Nacional.

Linnaeus, C. 1758. Systema naturae per regna trianaturae, secundum classes, ordines, genera,species, cum characteribus, differentiis, synony-mis, locis. 10th ed., tomus 1. Holmiae [Stock-holm]: Laurentii Salvii.

Matschie, P. 1916. Bemerkungen uber die GattungDidelphis L. Sitzungsberichte der Gesellschaft


Naturforschender Freunde zu Berlin 1916:259–272.

Mayr, E., E.G. Linsley, and R.L. Usinger. 1953.Methods and principles of systematic zoology.New York: McGraw-Hill.

Mones, A., and M.A. Klappenbach. 1997. Unilustrado aragones en el virreinato del rıo de LaPlata: Felix de Azara (1742–1821). Estudiossobre su vida, su obra, y su pensamiento. Analesdel Museo Nacional de Historia Natural deMontevideo (2) 9: i–viii, 1–231.

Musser, G.G., and M.D. Carleton. 2005. Super-family Muroidea. In D.E. Wilson and D.M.Reeder (editors), Mammal species of the world.3rd ed.: 894–1531. Baltimore, MD: JohnsHopkins University Press.

Musser, G.G., M.D. Carleton, E.M. Brothers, andA.L. Gardner. 1998. Systematic studies of oryzo-myine rodents (Muridae, Sigmodontinae): diagno-ses and distributions of species formerly assignedto Oryzomys ‘‘capito.’’ Bulletin of the AmericanMuseum of Natural History 236: 1–376.

Myers, P. 1982. Origins and affinities of themammal fauna of Paraguay. In M.A. Maresand H.H. Genoways (editors), Mammalianbiology in South America (Special PublicationSeries 6): 85–93. Linesville, PA: PymatuningLaboratory of Ecology.

Myers, P., and M.D. Carleton. 1981. The speciesof Oryzomys (Oligoryzomys) in Paraguay andthe identity of Azara’s ‘‘Rat sixieme ou rat atarse noir.’’ Miscellaneous Publications of theMuseum of Zoology University of Michigan161: i–iv, 1–41.

Oken, L. 1816. Lehrbuch der Naturgeschichte.Dritter Theile[:] Zoologie. Jena: August Schmidt.

Olfers, I. [F.J.M.] von. 1818. Bemerkungen zuIlliger’s Ueberblick der Saugthiere nach ihrerVertheilung uber die Welttheile, rucksichtlichder Sudamericanischen Arten (Species). In W.L.von Eschwege (editor), Journal von Brasilien,oder vermischte Nachrichten aus Brasilien, aufwissenchaftlichen Reisen gesammelt: 192–237.Weimar: Im Verlage des Gr. H.S. priv. Landes-Industries-Comptoirs.

Oliveira, J.A. de. 1998. Morphometric assessmentof species groups in the South American rodentgenus Oxymycterus (Sigmodontinae), with tax-onomic notes based on the analysis of typematerial. Unpublished Ph.D. dissertation, TexasTech University.

Palma, R.E. 1995. The karyotypes of two SouthAmerican mouse opossums of the genus Thyla-mys (Marsupialia: Didelphidae) from the An-des, and eastern Paraguay. Proceedings of theBiological Society of Washington 108: 1–5.

Palma, R.E. 1997. Thylamys elegans. MammalianSpecies 572: 1–4.

Paynter, R.A., Jr. 1989. Ornithological gazetteer ofParaguay. 2nd ed. Cambridge, MA: Museum ofComparative Zoology (Harvard University).

Paynter, R.A., Jr. 1995. Ornithological gazetteer ofArgentina. 2nd ed. Cambridge, MA: Museum ofComparative Zoology (Harvard University).

Pine, R.H., and C.O. Handley, Jr. 2008. GenusMonodelphis Burnett, 1830. In A.L. Gardner(editor), Mammals of South America. Vol. 1.Marsupialia, Insectivora, Edentata, Chiroptera:82–107. Chicago: Chicago University Press.

Rode, P. 1941. Catalogue des types de mammiferesdu Museum National d’Histoire Naturelle. II.Ordre des chiropteres. Paris: Museum Nationald’Histoire Naturelle.

Sanchez-Hernandez, C., and M.de L. Romero–Almaraz. 2003. Redescription of Sturnira liliumlilium and Sturnira lilium parvidens (Chiroptera:Phyllostomidae). Southwestern Naturalist 48:437–441.

Short, L.L. 1975. A zoogeographic analysis of theSouth American Chaco avifauna. Bulletin of theAmerican Museum of Natural History 154 (3):163–352.

Solari, S. 2003. Diversity and distribution ofThylamys (Didelphidae) in South America, withemphasis on species from the western side of theAndes. In M. Jones, C. Dickman, and M.Archer (editors), Predators with pouches, thebiology of carnivorous marsupials: 82–101.Collingwood, VIC: CSIRO Publishing.

Stein, B.R., and J.L. Patton. 2008. Genus Lutreo-lina O. Thomas, 1910. In A.L. Gardner (editor),Mammals of South America, vol. 1. (Marsupi-alia, Insectivora, Edentata, Chiroptera): 14–17.Chicago: Chicago University Press.

Tate, G.H.H. 1932. The South American Criceti-dae described by Felix Azara. American Muse-um Novitates 557: 1–5.

Tate, G.H.H. 1933. A systematic revision of themarsupial genus Marmosa with a discussion ofthe adaptive radiation of the murine opossums(Marmosa). Bulletin of the American Museumof Natural History 66 (1): 1–250, 26 pls., foldingtables.

Temminck, C.J. 1824 [1827] . Deuxieme mono-graphie sur le genre sarigue (1)–Didelphis.(Linn.). In Monographies de mammalogie, oudescription de quelques genres de mammiferes,dont les especes ont ete observees dans lesdifferens musees de l’Europe 1: 21–54, pls. 5, 6.Paris: G. Dufour et Ed. d’Ocagne.

Thomas, O. 1888. Catalogue of the Marsupialiaand Monotremata in the collection of the BritishMuseum (Natural History). London: BritishMuseum (Natural History).

Thomas, O. 1894. On Micoureus griseus Desm.,with the description of a new genus and species


of Didelphyidae. Annals and Magazine of

Natural History (6) 14: 184–188.

Thomas, O. 1896. On new small mammals from

the Neotropical region. Annals and Magazine of

Natural History (6) 18: 301–314.

Thomas, O. 1900. List of the mammals obtained

by Dr. Franco Grillo in the province of Parana,

Brazil. Annali del Museo Civico di Storia

Naturale di Genova (2) 20: 546–549.

Thomas, O. 1902. On Marmosa marmota andelegans, with descriptions of new subspecies of

the latter. Annals and Magazine of Natural

History (7) 10: 158–162.

Thomas, O. 1911. The mammals of the tenth

edition of Linnaeus; an attempt to fix the types

of genera and the exact bases and localities of

the species. Proceedings of the Zoological

Society of London 1911: 120–158.

Thomas, O. 1912. Three new small mammals from

S. America. Annals and Magazine of Natural

History (8) 9: 408–410.

Thomas, O. 1921. Three new species of Marmosa,

with a note on Didelphys waterhousei, Tomes.

Annals and Magazine of Natural History (9) 7:

519–523.

Thomas, O. 1923. The geographical races of

Lutreolina crassicaudata. Annals and Magazineof Natural History (9) 11: 583–585.

Velazco, P.M. 2005. Morphological phylogeny of

the bat genus Platyrrhinus Saussure, 1860

(Chiroptera: Phyllostomidae) with descriptions

of four new species. Fieldiana Zoology New

Series 105: i–iv, 1–53.

Voss, R.S., and R. Angermann. 1997. Revisionary

notes on Neotropical porcupines (Rodentia:Erethizontidae). 1. Type material described by

Olfers (1818) and Kuhl (1820) in the Berlin

Zoological Museum. American Museum Novi-

tates 3214: 1–42.

Voss, R.S., and S.A. Jansa. 2003. Phylogenetic

studies on didelphid marsupials II. Nonmolec-

ular data and new IRBP sequences: separate

and combined analyses of didelphine relation-

ships with denser taxon sampling. Bulletin of the

American Museum of Natural History 276:1–82.

Voss, R.S., and S.A. Jansa. 2009. Phylogeneticrelationships and classification of didelphidmarsupials: an intact radiation of New Worldmetatherian mammals. Bulletin of the AmericanMuseum of Natural History 322: 1–177.

Voss, R.S., D.P. Lunde, and N.B. Simmons. 2001.The mammals of Paracou, French Guiana: aNeotropical lowland rainforest fauna. Part 2.Nonvolant species. Bulletin of the AmericanMuseum of Natural History 263: 1–236.

Voss, R.S., T. Tarifa, and E. Yensen. 2004. Anintroduction to Marmosops (Marsupialia: Di-delphidae), with the description of a new speciesfrom Bolivia and notes on the taxonomy anddistribution of other Bolivian congeners. Amer-ican Museum Novitates 3466: 1–40.

Wagner, A. 1847. Beitrage zur Kenntniss der Saug-thiere Amerika’s. Abhandlungen der Mathemisch-Physikalischen Classe der Koniglich BayerischenAkademie der Wissenschaften 5: 121–208, pls.II–IV.

Wagner, J.A. 1855. Die Saugthiere in Abbildungennach der Natur mit Beschreibungen von Dr.Johann Christian Daniel von Schreber. Supple-mentband. Funfte Abtheilung: Die Affen,Zahnluder, Beutelthiere, Hufthiere, Insekten-fresser und Handfluger. Leipzig: L.D. Weigel.

Wetzel, R.M., and J.W. Lovett. 1974. A collectionof mammals from the Chaco of Paraguay.University of Connecticut Occasional PapersBiological Science Series 2: 203–216.

Whitehead, P.J.P. 1979. Georg Markgraf andBrazilian zoology. In E. Van den Boogaart,H.R. Hoetink, and P.J.P. Whitehead (editors),Johan Maurits van Nassau-Siegen 1604–1679,essays on the occasion of the tercentenary of hisdeath: 424–471. The Hague: Johan Maurits vanNassau Stichting.

Ximenez, A. 1967. Contribucion al conocimientode Lutreolina crassicaudata (Desmarest, 1804) ysus formas geograficas (Mammalia-Didelphi-dae). Comunicaciones Zoologicas del Museode Historia Natural de Montevideo 112: 1–7.


APPENDIX 1

TRANSLATED DESCRIPTIONS FROM

THE APUNTAMIENTOS

These are free English renderings of Azara’s (1802,vol. 1: 209–263) opossum accounts. In preparing thesetranslations, we often inserted verbs and other partsof speech omitted in his semitelegraphic Spanishdescriptions, as otherwise the style would appear tooeccentric for easy comprehension. Such minor inser-tions are not indicated as such below, but substantiveeditorial comments are enclosed in square brackets.Where the exact translation of certain words seemeduncertain, the original Spanish is quoted parentheti-cally. Because biological nomenclature should notrequire Talmudic parsing of ancient texts, we did nottry to eliminate or explain all of the ambiguitiesinherent in these agreeably nontechnical accounts,which are chiefly of historical rather than scientificinterest.

We omitted some anecdotal material (indicated byellipses) that has no obvious relevance for theidentification of the species in question. Likewise,we do not include Azara’s lengthy discussions ofAmerican marsupials previously described by Buffon,Daubenton, and other contemporaneous naturalists.However, we retained all details, no matter howtrivial, that concern the morphology, species-specificbehavior, or geographical origin of Azara’s ownmaterial. In combination with the main facts of eachaccount, these minor details are sometimes telling.

Azara used morphometric data to supplement hisqualitative descriptions, but he only explained how afew of his standard measurements were taken. Totallength (‘‘longitud’’) was measured with a cord passedalong the dorsal midline from the tip of the snout tothe tip of the tail; anterior height (‘‘altura delante’’)was measured from the withers to the tip of thelongest claw of the manus; posterior height (‘‘alturadetras’’) was measured from the highest point on thehip to the tip of the longest claw of the pes; anteriorcircumference (‘‘circunferencia delante’’) was mea-sured around the chest where it joins the forelimbs;and posterior circumference (‘‘circunferencia detras’’)was measured around the flanks. Unhelpfully, Azarasaid that he measured the tail in the same way that hemeasured total length, leaving the interpretation ofthis important dimension somewhat ambiguous forlack of a definite anterior endpoint.

Because Azara’s qualitative descriptions are limitedto behavioral and external-morphological traits, hismeasurements of the upper jaw (‘‘mandibula superi-or’’) are puzzling anomalies. On the assumption thatthis dimension was not obtained from osteologicalpreparations, we tried to replicate his reported valuesusing externally visible features of museum specimensin various ways. The best matches we obtainedsuggest that he measured the upper jaw across thebases of the left and right canine teeth. On the sameassumption, his measurements of the canine wereprobably made from the gumline (not the bonyalveolar margin) to the apex of the tooth.

Azara’s basic measurement units were ‘‘pulgadasdel pie de rey de Paris,’’ or inches (twelfths) of the oldFrench foot (pied du roi). In addition, he measuredsmall structures in ‘‘lineas,’’ which correspond to thelignes of French watchmakers. According to Dartonand Clark (1994) the metric equivalents of theseobsolete units are 1 pulgada 5 27.073 mm and 1 linea5 2.256 mm; therefore, we used these conversionfactors to compute the values provided in squarebrackets throughout the following accounts.

Of the Micure

The Guaranis give it this name, whose last syllablemeans ‘‘stinking,’’ and the Spaniards call it comadreja.It is not uncommon in Paraguay, nor in Buenos Aires,and it hides itself in tall grass and in holes in theground made by itself or by other animals; but it alsoinhabits the forests and the edges of woods and climbstrees to eat fruit. One captive adult individualpermitted its owner, but no other person, to handleit for eight days without showing gratitude; andalthough it did not want to eat meat, because it wasgiven oranges and beef blood: I have seen that otherindividuals eat only meat. Invariably this animalurinates and defecates when it is annoyed, dispersing avery bad smell that can be irritating, although itdissipates in a few hours with ventilation and is notsufficient to prevent the animal from being killed andeaten by my wild cats.

Along the abdomen of the female there is a slit oropening like that which results when a fat manunfastens some buttons of his waistcoat (‘‘chupa’’).Inside, along the borders or folds, there is a cavitythat increases in size to the rear; such that at thefront it is nothing, and in the rear where the cavitiesof the sides are united, it is already a capaciouspouch, which extends internally to the pubis. In theinterior of the cavity, which opens and shuts at willby parting or uniting the lips of the slit, one finds 13teats, one in the middle and the rest on the peripheryof an ellipse. One adult female had only 11 teats, andanother, which was not quite adult with the pouchand its lips not very perceptible, also had 11 teats;from which I infer that the number of them variesfrom 11 to 13, and that the females do not have aperceptible pouch until they need it, as one noticesfrom the cubs. . . .

Although some adults do not exceed 26J inches[711 mm], I will describe the largest I have seen. Totallength 30 inches [812 mm]: tail 13N inches [356 mm],of which 4J inches [115 mm] are furred, the rest tothe tip with only extremely sparse hairs that scarcelyemerge from the scales. The tail is round [in crosssection], except the prehensile part, where there issome flattening on the underside. Its circumference atthe base is 25=6 inches [77 mm]: the circumference ofthe body where the forelimbs join the trunk is 9Kinches [257 mm], and the circumference around theflanks is 9L inches [264 mm]. The height in front is8N inches [221 mm], and the height behind is 8Kinches [230 mm]. The greatest width of the head is 2Jinches [61 mm], the length of the head is 4K inches[122 mm], and from the front of the ear to the tip of


the snout is 3K inches [95 mm]. The upper jawexceeds 7 lines [16 mm]; and the biggest whiskers, laidback toward the ear, almost touch it, and others goupward. Behind the angle of the mouth there areseven long hairs or whiskers [the genal vibrissae], thelower ones white and the rest black. The ear is twoinches [54 mm] in height, 1L inches [47 mm] inbreadth, eliptical, very thin, dark at the base, the restwhite, and more drooping (‘‘mas caida’’) than in theother species. The canine teeth are 6 lines [14 mm],and the nostrils are separated from each other by awhite groove. The middle and longest finger of thehand is 9 lines [20 mm]. The scrotum is dark, withshort straw-colored fuzz. The testicles are 11 lines[25 mm] long, 7 lines [16 mm] in thickness in front,less behind, have a stem, and are separated in life 7lines [16 mm] from the body by the skin that enclosesthe ligaments and begins in the orifice [cloaca]. Thedead and pulled-out penis [i.e., drawn from the cloacaof a dead animal] extends 20 lines [45 mm] from theanus, half of which is cylindrical and the rest dividedto the tip into two little members each of which is 2Klines [6 mm] in diameter, being cylindrical for two-thirds of their length and then tapering to a point. Thefemale has the two passages [urogenital and rectalducts] in one orifice.

A dark marking begins behind the eye andnarrowly surrounding it continues to the whiskers.Another somewhat blacker marking begins on thecenter of the snout in front of the tear duct [anteriorcanthus of the eye] and extends upward to betweenthe ears, where it greatly expands and continues to thenape. The arms and legs are black, and the fur belowthe radius and on the metatarsus and face is veryshort. All the rest of the coat has two kinds of hairs:the shorter kind is abundant, dense, and soft yellowishwhite, with the points black on all of the dorsum andflanks, and between the arms, although one noticesthe black more along the face, flanks, and tail. Theother type of hair is two inches [54 mm] long, whitish,thick, sparse, erect, and emerges notably above theother, more on the back and toward the tail andflanks. Both kinds of hairs are intermingled, soft, lax,not stiff, and whatever pressure or breeze has apaintbrush-like effect on them (‘‘los apincela’’); thatis, they are so accumulated that joining together manyblack tips, form something like patches, leavingwhitish holes [i.e., the cumulative effect is thatbunching together the blackish tips of the overfurexposes the whitish underfur]. The [proximal] threeinches of naked tail are blackish, and the rest to thetip yellowish white. An albino or entirely whiteindividual was caught in Misiones.

Of the Lanoso

I have not seen any but the present male, which wasgiven me in Paraguay by Don Garcıa Francia,assuring me, as others have, that the female has apouch similar to that of the Micure, where it puts theyoung. It was given to me dead, and to this I attributethe fact that it did not smell bad. I described it when Idid not have the knowledge that I do today; and

putting it in alcohol, I sent it to the Royal Cabinet ofMadrid.

Total length 22N inches [600 mm]: tail 13K inches[365 mm], of which the terminal part is hairless for4K inches [122 mm] dorsally and 9 inches [244 mm]ventrally. Its circumference at the base is 19 lines[43 mm]; and it is not conical or round [in cross-section], but prismatically triangular with the anglesvery beveled, and a sort of canal follows the ventralmidline. The circumference of the body is 5 inches[135 mm]. Head length 2J inches [61 mm], width 1Kinches [41 mm] between the ears, and decreasing tothe point of the snout, which has a groove thatseparates the nostrils. The whiskers are black and verylong. There are also some [the genal vibrissae] behindand below the eye, whose iris is the color of vicugnawool. Equally there are some blond hairs behind theeye, and white ones in the canal of the lower jaw [theinterramal vibrissae]. The ear is 12 lines [27 mm] high,6 lines [14 mm] in width, elliptical, somewhatdrooping (‘‘caida’’), hairless inside and half hairlesson the outside, very thin, purple, and near the anteriorbase there is a point that projects from the border.The upper jaw exceeds 4 lines [9 mm]: it has 10incisors: the middle ones, which are somewhat longerand stouter, form a spandrel at the point [i.e., theyconverge at their tips, creating an open triangularspace between them]. Below there are eight incisors,which leave a gap in the middle that is filled by thetwo long upper ones; where furthermore one sees twocanine teeth separated by a gap on each side, theexterior and largest of which is 4 lines [9 mm]. Thelower canines and molars in total are 16 [i.e., there are16 lower teeth counting those on both sides, inaddition to the eight lower incisors]. The scrotum,which lacks fur and is pale blue, hangs down 10 lines[23 mm]. The testicles are 6 lines [14 mm] in diameterwith a nipple (‘‘pezon’’ [presumably the epididymis])on the underside, and they are excessively compressed(‘‘demasiado oprimidos’’[?]).

Arising from the snout is a dark streak one line[2 mm] wide, that continues until it ends on the nape.The outline of the eye [i.e., the circumocular mask] isbright reddish brown; and between it and theaforementioned streak there is light grayish brown.The occiput, the fronts and sides of the arms, the frontof the legs, and the tarsus, are reddish-tobaccocolored. The midback (‘‘espinazo’’) is the same,although more opaque; and the rest of the body ispale grayish brown, much paler ventrally, andbetween the fore- and hind limbs. The fur of the faceis very short: that of the back, tail, and the posteriorpart of the legs is one inch [27 mm] long, and over therest of the body not so long; but all very dense,woolly, soft, and excellent for lining clothes. Thenaked part of the tail is white. My friend Don PedroBlas Noseda caught another male in the country atabout 27u [S latitude], and fed it for some days withwatermelon, because it did not want to eat meat.

Of the Coligrueso

Although all of the opossums have very thick tails,that of this one is so thick at the base, that it almost


appears a continuation of the body; and the animalsupports itself less with the tail than do theaforementioned species. The ears are smaller, lessrounded, and somewhat more upright; and the face isnot so flat, nor the snout as long and pointed, nor isthere a groove between the nostrils, and the neck is asthick as the head. In a rural house I saw one tied to abench; and I noted that it had dug a shallow hole inthe dirt floor, and that a tame parrot havingapproached, it killed the bird instantly. It alloweditself to be handled, despite being an adult, and havingbeen captured only a few days before. It was fed withraw meat: I gave it a dead mouse, and it ate the head.It seemed to me as stupid, quiet, and torpid as theMicure, and I did not notice a bad odor, perhapsbecause I did not see it irritated. Neither did I noteany smell from two other identical males, nor fromtwo females that I had. It lives in Paraguay andBuenos Ayres in the fields, entering houses at timesfor the same purpose as the Micure.

Total length 23 inches [623 mm]: tail 11 inches[298 mm], round [in cross section], and its circumfer-ence at the base 2K inches [68 mm]. The anteriorcircumference of the body 6O inches [180 mm], andbehind 6L inches [183 mm]. Beneath the eye is a clearcinnamon color, which turning the corner at the angleof the mouth, and occupying all of the underside ofthe head, continues for all of the underside of theanimal. The hands, feet, and face from the eyesforward, are darker; and the rest without exceptionhardly differs in coloration from the little housemouse, its fur not much longer than that of the rat.Somewhat more than a third of the tail has fur likethat of the body; and the rest is hairless with sparseshort black hairs that arise from between the scales,also black, except for the terminal 1K inches [41 mm]that are white. The scrotum is hairy and pendent as inall the opossums.

They sold me a female, saying that it had been seento kill a viper. Its total length was 20 inches [541 mm]:tail 8L inches [237 mm] long, two inches [54 mm]around at the base. It only differs from the male inthat the clear cinnamon color in that one was in thisone white or yellowish white. In place of the pouch ofthe previously described females, it [the femalecoligruesa] has between its hind legs two obviousfolds, open in an ellipse, that enclosed a very smallsinus. Inside the folds were the teats in the peripheryof another long concentric ellipse; with the oddfeature that there were four teats on the right side,two on the left, and none in the middle. Anotheryoung female was the same, except that the folds werehardly perceptible, and I did not count the teats.Those of the first [female] were so noticeable, that itseemed to me they had only recently been suckled:and also I had neglected to observe with greater care,if those that were lacking on the left side and in thecenter, were simply not suckled [and thereforeundeveloped].

In addition to the aforementioned specimens Icaught two identical males, a young one of 15 inches[406 mm], and the other of 21 inches [569 mm]. Thetail of this one was 10 inches [271 mm]: the circum-ference around the body where the arms join was 5Oinches [153 mm], and behind a little less. The whiskers

were almost 3 inches [81 mm]: and the difference inthe pelage consisted, in that the bright cinnamon-colored area of the first male was in this one brighttobacco red; and the rest of the coat of the sametobacco based on grey-brown. The scrotum hung 9lines [20 mm], and the canine tooth had 5 lines[11 mm].

Of the Colilargo

I have not seen any [specimen] but the present one,which Don Josef Casal caught in his country houseand sent to me, writing that it is called anguya-guayquıin Paraguay; but as no one can make sense of such aname, whose first part means ‘‘mouse,’’ and whosesecond part no one understands, I have judged it moreconvenient to call it colilargo, because it is [long-tailed].

Total length 8L inches [237 mm]: tail 5 inches[135 mm], all naked, very soft and shiny (‘‘lustrosa’’).The scrotum lacks fur, and does not hang as in theother species, and this circumstance, and the fact thatthe testicles are very tiny and inactive [‘‘holgados’’],leaves me in no doubt that this individual is not anadult. One line’s width [ca. 2 mm] around the eye isblack and notable [i.e., there is a prominent circumo-cular mask]. Outside this ring there is another whitishone , and between it and the other eye there is a darkline that terminates at the level of the tear duct(‘‘lagrimal’’). Between the ears, all of the dorsum, andthe tail, are colored like the house mouse; but the sidesof the body are paler, especially the sides of the arms.The lower jaw, the underside of the head, and theanterior of the arms, are almost white, and the rest ofthe venter is dirty white. All of the pelage is as softand short as that of the aforementioned house mouse,and perhaps more so.

Of the Colicorto

Thus I call it for the brevity of its tail bycomparison with other opossums, and deprecate thename anguya (mouse) which the Guaranıs give it. Ihave only had two males, caught in the countrysidebelow the 27th and 34th parallels [of S latitude].Another was brought to my friend Noseda, which heput in a cage; and having escaped, it entered theburrows of some common rats; which ganged up tothrow it out and persecuted it, compelling it to fleeand cry repeatedly che che. Noseda responded to thesecries, and having caught it, he returned it to the cage,where it died in a month. It ate little, and afterward itrubbed its snout very rapidly with its hands. Myfriend fed it raw meat, and amused himself byshowing it to the animal from a distance, becausethis much annoyed it, leaping and squeaking in orderto grab it. One day he gave it a little mouse, andkilling it in a moment, it ate the entrails leaving therest. It drank hastily with its tongue, and after a fewdays was very tame; but when irritated, it discharged abad odor, although not strong.

Length 6L inches [183 mm]: tail 2J inches[61 mm], very thick and hairless, less than 3 lines


[7 mm, presumably in diameter] at the base. Circum-ference in front, 3K inches [95 mm], around the belly4 inches [108 mm]. The ear 4 lines [9 mm] high, 6 lines[14 mm] wide, hairless, and more erect and smallerthan those of other opossums. The body is moreflattened, thicker, and stubbier than all the rest of theopossums, and the scrotum hangs much, being dark-skinned with short whitish fuzz. The male thatNoseda described was 8K inches [230 mm] long,and the other measurements in proportion.

All of the pelage is short and soft like that of themouse. Under the eye and a very little bit above it, allof the side of the head and of the body to the tail isbright cinnamon; and the underside is somewhatlighter. Over the snout it is grizzled brown (‘‘pardo’’),and all the rest of the animal is frosted grayish brown(‘‘pardo aplomado’’), or rather a mixture, becausesome hairs have whitish points, which one sees amongthe others.

Besides the observations cited above that I made ofcaptive animals, Noseda wrote me as follows. ‘‘On the13th of December I was brought a female with 14cubs, dead or moribund, of hurts given them uponcapture and afterward. Nevertheless, placing themnear the teats, the two hardiest pups took the teats;but the mother starting to run about, they could notcontinue [suckling] from their weakness, dying on thethird day. There were something like eight that hadbeen born, according to those who chased the mother[another female?] at that time without being able tocatch her; and they said, that the young dragged onthe ground as the mother ran without loosening theirhold on the teats. When I saw them they were naked,blind, and 1K inches long, without the tail of 4 lines[9 mm]. They were found with the mother in aswampy patch of tall grass (‘‘pajonal del campo’’);and having hidden in a hole in the ground, it wasflooded with water, making her leave and run with theyoung dragging along, as they were when they went inthe hole, because she never left them behind. She didnot have a pouch; but one could see between the hindlegs a swollen udder, that encroached a little towardthe belly; and in this were 14 teats, so small that onecould hardly count them. The milk dried up severaldays after the death of the young, at which time it wasnecessary to use a magnifying glass to see the teats. Idid not notice a bad smell as I did in the male. Herlength was 6 4/5 inches [184 mm]: the tail 2 inches[54 mm]. The bright cinnamon color of the male wasonly seen on the sides of the head and of the neck,because the sides of the body were made grizzledbrown (‘‘pardeaba’’) by being blended with thegrayish color of the back. The underparts were alighter cinnamon (‘‘bayas acaneladas’’) or whitishcinnamon (‘‘acaneladas blanquizcas’’).’’

Of the Enano

I don’t know another name that suits it better, norhave I had but two identical males, which were sold tome on different days in October by Indians of SanIgnacio Guazu, saying that they had caught them intheir huts.

Length 7 inches [190 mm]: tail 3 b inches [99 mm],all naked, and somewhat more slender in proportionto that of the Colilargo. The ear is quite upright androunded, 6 lines [14 mm] high and 4 lines [9 mm]wide. The whiskers are much finer than those of thecommon little mouse, and the testicles pendant and alittle loose in the scrotum. Together they are 5 lines[11 mm] in diameter; which makes me believe that theindividuals are adults. I did not notice a bad odor.

The fur is short and soft like that of theaforementioned mouse. The narrow outline of theeye is of a blackness that extends to the tear duct(‘‘lagrimal’’), and the eyebrow above this color isfaintly whitish, there being between it and the other adark triangle that is scarcely noticeable. Between theears, over the whole dorsal surface of the animal, theflanks, and on the outside of the four legs, aresomewhat darker gray than the aforementioned littlemouse, which is present [which was compared with itat the same time?]. Under the eye on the upper jawthere is a patch of yellowish white; and under thehead, all the ventrum, and the insides of the legs, is awhitish more clear than that of the aforementionedmouse. The tail is somewhat lighter [in color] than thebody; and the scrotum is dark with short white fuzz.

APPENDIX 2

Gazetteer

Below are listed all of the localities from which weexamined specimens of Thylamys macrurus and T.pusillus in the course of this study. Italicized placenames are those of the largest political divisions (state/department/province) within countries; boldface iden-tifies collection localities as they appear in the text ofthis report. Unless recorded by the collector, geo-graphic coordinates and elevation above sea level (inmeters, m) are provided in square brackets with acited secondary source for these data. Numberedlocalities are plotted on the accompanying map(fig. 3).

BOLIVIA

1. Chuquisaca, 3.8 km by road E Carandayti(20u469S, 63u039W, 480 m): Thylamys pusillus(coll. B.R. Riddle, 10 July 1985).

2. Santa Cruz, 53 km E of Boyuibe (20u279S,62u509W, 600 m): Thylamys pusillus (coll. S.Anderson and M.L. Campbell, 6–8 July 1991).

3. Santa Cruz, Tita (18u259S, 62u109W, 300 m):Thylamys pusillus (coll. J.A. Cook, 19 October1984).

4. Tarija, Estancia Bolıvar (21u389S, 62u349W,400 m): Thylamys pusillus (coll. S. Anderson,F. Guerra, and R. de Urioste, 18–20 August1991).

5. Tarija, 8 km S [and] 10 km E Villa Montes([21u199S, 63u259W; Anderson, 1997], 467 m), Ebank R. Pilcomayo: Thylamys pusillus (coll. G.Schmitt, 30 April–7 May 1979).


BRAZIL

6. Mato Grosso do Sul, Campo Grande [20u279S,54u379W, 543 m; Carmignotto and Monfort,2006]: Thylamys macrurus (coll. J.L. Lima, 13June 1930).

7. Mato Grosso do Sul, Fazenda California[20u419S, 56u529W, 650 m; Carmignotto andMonfort, 2006]: Thylamys macrurus (coll. A.P.Carmignotto, 14–15 April 2002).

8. Mato Grosso do Sul, Fazenda Santa Terezinha[20u509S, 56u379W, 615 m at Bonito; Car-mignotto and Monfort, 2006]: Thylamys ma-crurus (coll. N.C. Caceres, 26 June 2002).

PARAGUAY

9. Alto Paraguay, Destacamento Militar GabinoMendoza (20u039S, 61u519W, 420 m): Thylamyspusillus (coll. F. Pintos, 21 May 1997).

10. Alto Paraguay, Fortın Pikyrenda (20u059S,61u479W, 420 m): Thylamys pusillus (coll. F.Pintos, 21–22 May 1997).

11. Alto Paraguay, Palmar de las Islas (19u379S,60u319W, 150 m): Thylamys pusillus (coll. S.J.Presley, 9 May 1997).

12. Amambay, 28 km SW Pedro Juan Caballero[22u389S, 55u579W, no elevation; DMA1992]:Thylamys macrurus (coll. T.W. Nelson, 1–11December 1976, 9 February 1977).

13. Boqueron, Estancia ‘‘El 43’’ (21u569S, 60u159W,80 m): Thylamys pusillus (coll. F. Pintos, 18August 1995).

14. Boqueron, Estancia Toledo, 35 km W Filadelfia[ca. 22u219S, 60u239W; estimated from map]:Thylamys pusillus (coll. C.J. Yahnke, 14 March1997).

15. Boqueron, Experimental Farm, 11 km W Fila-delfia [ca. 22u219S, 60u099W; estimated frommap]: Thylamys pusillus (coll. C.J. Yahnke, 17June 1997).

16. Boqueron, Guachalla [5 Fortın Guachalla at22u279S, 62u209W, ca. 250 m; Paynter, 1989]:Thylamys pusillus (coll. P. Willim, 14 August1945).

17. Boqueron, Orloff [5 Colonia Mennonita at22u309S, 60u009W, ca. 175 m; Paynter, 1989]:Thylamys pusillus (coll. J. Unger, 17 January1946).

18a. Boqueron, Parque Nacional Teniente AgripinoEnciso (21u099S, 61u329W, 250 m): Thylamyspusillus (coll. S.J. Presley, 23 March 1997).

18b. Boqueron, Parque Nacional Teniente AgripinoEnciso, near Puesto Siracua (from 21u039S,61u459W to 21u029S, 61u469W, 255 m): T.pusillus (coll. C.W. Dick, G. Gonzalez, and I.Mora, 25–27 September 1998).

19. ‘‘Boqueron,’’ Parque Cue (20u089S, 61u489W,390 m): Thylamys pusillus (coll. S.J. Presley, 8September 1996). This locality is actually in thedepartment of Alto Paraguay.

20. Boqueron, Schmidt Ranch, 10 km E Corrales[ca. 22u259S, 60u279W; estimated from map]:Thylamys pusillus (coll. C.J. Yahnke, 10 May1997).

21. Boqueron, 410 km NW Villa Hayes [ca. 22u349S,59u489W]: Thylamys pusillus (coll. P. Myers, 24September 1973).

22. Boqueron, 460 km NW Villa Hayes [ca. 22u229S,60u129W]: Thylamys pusillus (coll. P. Myers, 7April 1973).

23. Central, Asuncion [25u169S, 57u409W, 77 m;Paynter, 1989]: Thylamys macrurus (N.L. Hold-en, probably ca. 1899).

24. ‘‘Chaco,’’ 50 km WNW Fortın Madrejon[20u269S, 60u199W]: Thylamys pusillus (coll. P.Myers, 7 August 1976). This locality is now inthe department of Alto Paraguay.

25. Concepcion, 7 km NE Concepcion, EscuelaAgropecuaria (23u219S, 57u239W, no elevation):Thylamys macrurus (coll. E. Palma, 25 Novem-ber 1992).

26. ‘‘Nueva Asuncion,’’ 1 km SW Km 620 Trans-Chaco Road [21u229S, 61u319W; estimated frommap]: Thylamys pusillus (coll. T.W. Nelson, 17February 1978). This locality is now in thedepartment of Boqueron.

27. ‘‘Nueva Asuncion,’’ 19 km by road WSW Km 588Trans-Chaco Road [21u369S, 61u269W; estimatedfrom map]: Thylamys pusillus (coll. T.W. Nel-son, 27 May–8 June 1978). This locality is nowin the department of Boqueron.

28. Paraguarı, Sapucay [5 Sapucaı at 25u419S,56u579W, ca. 220 m; Paynter, 1989]: Thylamysmacrurus (coll. W. Foster, ca. 1903).

29. Presidente Hayes, Estacion Experimental ChacoCentral, 2 km W Cruce Pioneros [23u149S,59u119W; estimated from map]: Thylamys pusil-lus (coll. C.J. Yahnke, 23 August 1997).

30. Presidente Hayes, 295 km NW Villa Hayes [ca.23u149S, 59u119W; estimated from map]: Thyla-mys pusillus (coll. P. Myers, 24 June 1972).


Documents

Chapter 11. The Six Opossums of Félix de Azara: Identification, Taxonomic History, Neotype Designations, and Nomenclatural Recommendations